Help with plpgsql - subst variable value

Hi all.

This my code snapshot:

CREATE FUNCTION CreateObject(varchar(600)) RETURNS int4 AS '
DECLARE
. . .
ObjectSeqName text;
BEGIN
. . ..
ObjectSeqName := ''ObjectLog'' || ObjectID || ''_Seq'';
CREATE SEQUENCE ObjectSeqName start 1 increment 1 maxvalue 2147483647
minvalue 1 cache 1 CYCLE;
. . .
END IF;
RETURN ObjectID;
END;
' LANGUAGE 'plpgsql';

When I run this function I got
ERROR: parser: parse error at or near "$1"

So how can get value of ObjectSeqName in sequence/table/etc. name?