Custom Data Control Problem

Hi all!
I developed and tested a data control using ADODB with vb6, and all was fine.

The problem is that when I use my custom data control in VB5, textboxes, listboxes etc. have their DataSource property empty.
So I can't bind any control to a database...

Where's the mistake? Is there an incompatibility between vb6 and vb5?

Thanks.
Kahlim