interaction between csps with dummy tlists and set_customscan_references

Hi,

Whilst developing a CSP that potentially sits (directly) above e.g. any
union or anything with a dummy tlist we observed some problems as the
set_customscan_references cannot handle any dummy tlists and will give
invalid varno errors. I was wondering how we can fix this, and I was
wondering what the reason is that there is actually no callback in the
csp interface for the set_customscan_references. Can someone maybe
clarify this for me?

Thanks!

Regards,
Luc