Agregate Components in ActiveX?

I have a C++ Builder component I created which combines TLabel, TEdit,
and TComboBox into a single control.  It works just fine in C++ Builder.

Now I want to move this component to an ActiveX control.  I've used the
wizard suggested in the documentation, and everything seems to go fine.
After registering the control, I attempt to drop it onto a form.
Unfortunately, what I get is a great big whopping white space where my
component should be.

I've tried the switching between building with runtime
packages/libraries and staticly linking, to no avail.  Just to make sure
that I hadn't goofed something up in my config, I also tried throwing a
wrapper around one of the standard VCL controls, and that control worked
perfectly (even in different development environments).

So is there something I'm doing wrong here?  Do Agregate Components not
get along well with ActiveX?  Who shot J.R.?