register an Com add-in

Dear support,
I’d like to build my custom import filter as an com add-in for Flexpro 7.0 (i use demo version, my customer use professional edition)in VB6.0. But the auto register action just get flexpro 6.0 library, I can not register that DLL under 7.0 object library.
Is it impossible for DEMO version to build such com add-in? or any other reasons or guides can tell me?
Thanks in advance for your great help.
Tanya

Thanks very much.