Shape text behavior: How can I doubleclick and edit the text

I have a stencil with shapes which are groups with polygons and a text box. I didn't create the stencil but I would like to make some changes.

If I double click on the existing shapes, I can edit the shapes text. If I ungroup the shape and make edits, I can no longer double click on the shape to edit the text.

Research has me delving into the mysteries of the shapesheet... and there are some "user-created cells" which exist on the old shapes but do not on my new shape... User.HasText, User.SoISH, and some others.

I would like to be able to place a text box in my shape which behaves the same as the old shape, but even creating these user defined cells does nothing for me. This seems like a relatively simple thing to do, and something you would want in most shapes... but the mojo to do this eludes me.

If you could point me in the right direction I would be greatly appreciative.

I use Visio 2003, and I have placed an example stencil in vss and vsx format on mediafire for inspection to illustrate my point. the "Works" shape functions as I want, double clicking edits the text. The "Doesn't Work" shape illustrates the current bane of my existence.

Download the stencils here http://www.mediafire.com/?7ubety9vdvs

Thanks in advance for ANY help.