diff --git a/src/pl/plpython/plpy_procedure.c b/src/pl/plpython/plpy_procedure.c
index a28cb9a..17e9dd1 100644
--- a/src/pl/plpython/plpy_procedure.c
+++ b/src/pl/plpython/plpy_procedure.c
@@ -193,6 +193,16 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("trigger functions can only be called as triggers")));
+				else if (procStruct->prorettype == CSTRINGOID){
+					/* do the real work */
+					PLy_output_datum_func(&proc->result, rvTypeTup);
+				}
+				else if (rvTypeStruct->typisdefined == false){
+					/* leave shell type as uninitialised */
+					proc->result.out.d.typoid = procStruct->prorettype;
+					proc->result.out.d.typmod = -1;
+					proc->result.is_rowtype = -1; 
+				}
 				else if (procStruct->prorettype != VOIDOID &&
 						 procStruct->prorettype != RECORDOID)
 					ereport(ERROR,
@@ -212,6 +222,10 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 				proc->result.out.d.typmod = -1;
 				proc->result.is_rowtype = 2;
 			}
+			else if ((fn_oid == rvTypeStruct->typinput)||
+					 (fn_oid == rvTypeStruct->typreceive)) {
+				PLy_output_datum_func_direct(&proc->result, rvTypeTup);
+			}
 			else
 			{
 				/* do the real work */
@@ -276,7 +290,22 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 				switch (argTypeStruct->typtype)
 				{
 					case TYPTYPE_PSEUDO:
-						/* Disallow pseudotype argument */
+						if ((types[i] == CSTRINGOID) ||
+							(types[i] == INTERNALOID)){
+							PLy_input_datum_func(&(proc->args[pos]),
+												types[i],
+												argTypeTup);
+							break;
+						}
+						if (argTypeStruct->typisdefined == false) {
+							/*
+							 * should be safe to leave shell type uninitialised
+							 * by the time the function is called, it will be a full type
+							 */
+							proc->args[pos].is_rowtype = -1;
+							break;
+						}
+						/* Disallow other pseudotype arguments */
 						ereport(ERROR,
 								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						  errmsg("PL/Python functions cannot accept type %s",
@@ -287,6 +316,14 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 						proc->args[pos].is_rowtype = 2;
 						break;
 					default:
+						/* type io functions do direct conversion  */
+						if ((fn_oid == argTypeStruct->typoutput) ||
+							(fn_oid == argTypeStruct->typsend)) {
+							PLy_input_datum_func_direct(&(proc->args[pos]),
+												 types[i],
+												 argTypeTup);
+							break;
+						}
 						PLy_input_datum_func(&(proc->args[pos]),
 											 types[i],
 											 argTypeTup);
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index 8f2367d..bb09472 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -41,8 +41,11 @@ static PyObject *PLyInt_FromInt32(PLyDatumToOb *arg, Datum d);
 static PyObject *PLyLong_FromInt64(PLyDatumToOb *arg, Datum d);
 static PyObject *PLyLong_FromOid(PLyDatumToOb *arg, Datum d);
 static PyObject *PLyBytes_FromBytea(PLyDatumToOb *arg, Datum d);
+static PyObject *PLyString_FromCString(PLyDatumToOb *arg, Datum d);
+static PyObject *PLyLong_FromInternal(PLyDatumToOb *arg, Datum d);
 static PyObject *PLyString_FromDatum(PLyDatumToOb *arg, Datum d);
 static PyObject *PLyList_FromArray(PLyDatumToOb *arg, Datum d);
+static PyObject *PLyBytes_FromRawType(PLyDatumToOb *arg, Datum d);
 
 /* conversion from Python objects to Datums */
 static Datum PLyObject_ToBool(PLyObToDatum *arg, int32 typmod, PyObject *plrv);
@@ -51,6 +54,9 @@ static Datum PLyObject_ToComposite(PLyObToDatum *arg, int32 typmod, PyObject *pl
 static Datum PLyObject_ToDatum(PLyObToDatum *arg, int32 typmod, PyObject *plrv);
 static Datum PLySequence_ToArray(PLyObToDatum *arg, int32 typmod, PyObject *plrv);
 
+static Datum PLyBytes_ToRawType(PLyObToDatum *arg, int32 typmod, PyObject *plrv);
+
+
 /* conversion from Python objects to composite Datums (used by triggers and SRFs) */
 static Datum PLyString_ToComposite(PLyTypeInfo *info, TupleDesc desc, PyObject *string);
 static Datum PLyMapping_ToComposite(PLyTypeInfo *info, TupleDesc desc, PyObject *mapping);
@@ -360,6 +366,107 @@ PLyObject_ToCompositeDatum(PLyTypeInfo *info, TupleDesc desc, PyObject *plrv)
 	return datum;
 }
 
+void
+PLy_output_datum_func_direct(PLyTypeInfo *ti, HeapTuple typeTup)
+{
+	PLyObToDatum *arg = &(ti->out.d);
+	Form_pg_type typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
+	
+	perm_fmgr_info(typeStruct->typinput, &arg->typfunc);
+	arg->typoid = HeapTupleGetOid(typeTup);
+	arg->typmod = -1;
+	arg->typioparam = getTypeIOParam(typeTup);
+	arg->typbyval = typeStruct->typbyval;
+	arg->typlen = typeStruct->typlen;
+	arg->typalign = typeStruct->typalign;
+	
+	arg->func = PLyBytes_ToRawType;
+
+}
+
+/*
+ * Convert a Python bytes to a PostgreSQL bytea datum.  This doesn't
+ * go through the generic conversion function to circumvent problems
+ * with embedded nulls.  And it's faster this way.
+ */
+static Datum
+PLyBytes_ToRawType(PLyObToDatum *arg, int32 typmod, PyObject *plrv)
+{
+	// copy of PLyObjecttoBytea now, will change if basic functioning is checked ok
+	PyObject   *volatile plrv_so = NULL;
+	Datum		rv;
+
+	Assert(plrv != Py_None);
+
+	plrv_so = PyObject_Bytes(plrv);
+	if (!plrv_so)
+		PLy_elog(ERROR, "could not create bytes representation of Python object");
+
+	PG_TRY();
+	{
+		char	   *plrv_sc = PyBytes_AsString(plrv_so);
+		size_t		len = PyBytes_Size(plrv_so);
+        size_t      size;
+		void	   *result;
+
+		/* return varlen types as bytea */
+		if (arg->typlen == -1) {
+			size = len + VARHDRSZ;
+			result = palloc(size);
+			SET_VARSIZE(result, size);
+			memcpy(VARDATA(result), plrv_sc, len);
+			rv = PointerGetDatum(result);
+		}
+		else {
+			size = arg->typlen;
+			if (len != size)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATA_EXCEPTION),
+						 errmsg("PL/Python type output conversion data length mismatch"),
+						 errdetail("Python length %d, PostgreSQL type length %d", (int)len, (int)size)));
+			if (arg->typbyval){
+				switch (size) {
+					case 1:
+						rv = ((Datum) SET_1_BYTE(*(uint8*)plrv_sc));
+						break;
+					case 2:
+						rv = ((Datum) SET_2_BYTES(*(int16*)plrv_sc));
+						break;
+					case 4:
+						rv = ((Datum) SET_4_BYTES(*(int32*)plrv_sc));
+						break;
+					case 8:
+						rv = ((Datum) SET_8_BYTES(*(int64*)plrv_sc));
+						break;
+					default:
+						ereport(ERROR,
+								(errcode(ERRCODE_DATA_EXCEPTION),
+								 errmsg("PL/Python type output conversion not supported for pass-by-value length: %d", (int)size)
+								 ));
+				}
+			}
+			else {
+				result = palloc(size);
+				memcpy(result, plrv_sc, len);
+				rv = PointerGetDatum(result);
+			}
+		}
+	}
+	PG_CATCH();
+	{
+		Py_XDECREF(plrv_so);
+		PG_RE_THROW();
+	}
+	PG_END_TRY();
+
+	Py_XDECREF(plrv_so);
+
+	if (get_typtype(arg->typoid) == TYPTYPE_DOMAIN) // ToDo: this should be probably cached as arg->typtype
+		domain_check(rv, false, arg->typoid, &arg->typfunc.fn_extra, arg->typfunc.fn_mcxt);
+	
+	return rv;
+}
+
 static void
 PLy_output_datum_func2(PLyObToDatum *arg, HeapTuple typeTup)
 {
@@ -422,6 +529,49 @@ PLy_output_datum_func2(PLyObToDatum *arg, HeapTuple typeTup)
 	}
 }
 
+/*
+ * convert PostgreSQL binary representation directly to python.
+ * This is used by types output() and send() functions which
+ * must manage the actual conversion
+ */
+
+void
+PLy_input_datum_func_direct(PLyTypeInfo *ti, Oid typeOid, HeapTuple typeTup)
+{
+	PLyDatumToOb *arg = &(ti->in.d);
+	Form_pg_type typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
+
+	/* Get the type's conversion information */
+	perm_fmgr_info(typeStruct->typoutput, &arg->typfunc);
+	arg->typoid = HeapTupleGetOid(typeTup);
+	arg->typmod = -1;
+	arg->typioparam = getTypeIOParam(typeTup);
+	arg->typbyval = typeStruct->typbyval;
+	arg->typlen = typeStruct->typlen;
+	arg->typalign = typeStruct->typalign;
+	
+	arg->func = PLyBytes_FromRawType;
+
+}
+
+/*
+ * convert postgresql datum directly to python bytes()
+ * used in type-io functions where real conversion is done in python
+ */
+static PyObject *
+PLyBytes_FromRawType(PLyDatumToOb *arg, Datum d)
+{
+	if (arg->typbyval) {
+		return PyBytes_FromStringAndSize((char*) &d, arg->typlen);
+	}
+	else {
+		bytea	   *var = DatumGetByteaP(d);
+		char	   *bytes = VARDATA(var);
+		size_t		size = (arg->typlen > 0)? arg->typlen: VARSIZE(var) - VARHDRSZ;
+		return PyBytes_FromStringAndSize(bytes, size);
+	}
+}
+
 static void
 PLy_input_datum_func2(PLyDatumToOb *arg, Oid typeOid, HeapTuple typeTup)
 {
@@ -467,6 +617,12 @@ PLy_input_datum_func2(PLyDatumToOb *arg, Oid typeOid, HeapTuple typeTup)
 		case BYTEAOID:
 			arg->func = PLyBytes_FromBytea;
 			break;
+		case CSTRINGOID:
+			arg->func = PLyString_FromCString;
+			break;
+		case INTERNALOID:
+			arg->func = PLyLong_FromInternal;
+			break;
 		default:
 			arg->func = PLyString_FromDatum;
 			break;
@@ -567,6 +723,23 @@ PLyBytes_FromBytea(PLyDatumToOb *arg, Datum d)
 }
 
 static PyObject *
+PLyString_FromCString(PLyDatumToOb *arg, Datum d)
+{
+	const char *txt = DatumGetCString(d);
+
+	return PyBytes_FromString(txt);
+}
+
+static PyObject *
+PLyLong_FromInternal(PLyDatumToOb *arg, Datum d)
+{
+	/* convert pgsql type 'internal' to integer so it can be used by ctypes */
+	void* p = DatumGetPointer(d);
+
+	return PyLong_FromVoidPtr(p);
+}
+
+static PyObject *
 PLyString_FromDatum(PLyDatumToOb *arg, Datum d)
 {
 	char	   *x = OutputFunctionCall(&arg->typfunc, d);
diff --git a/src/pl/plpython/plpy_typeio.h b/src/pl/plpython/plpy_typeio.h
index 82e472a..4648ddf 100644
--- a/src/pl/plpython/plpy_typeio.h
+++ b/src/pl/plpython/plpy_typeio.h
@@ -94,6 +94,9 @@ extern void PLy_typeinfo_dealloc(PLyTypeInfo *arg);
 extern void PLy_input_datum_func(PLyTypeInfo *arg, Oid typeOid, HeapTuple typeTup);
 extern void PLy_output_datum_func(PLyTypeInfo *arg, HeapTuple typeTup);
 
+extern void PLy_input_datum_func_direct(PLyTypeInfo *arg, Oid typeOid, HeapTuple typeTup);
+extern void PLy_output_datum_func_direct(PLyTypeInfo *arg, HeapTuple typeTup);
+
 extern void PLy_input_tuple_funcs(PLyTypeInfo *arg, TupleDesc desc);
 extern void PLy_output_tuple_funcs(PLyTypeInfo *arg, TupleDesc desc);