As is my wont, I have been shamelessly making liberal use of ideas from these forums (and these brains) and here is the net result. It is ugly, but it works.

If I've done this right, the PPT97/SR2 can be opened as would any PPT presentation, and the toolbar will show a macrobutton "AssignMacro".

Click that tool to obtain a GUI form.
Select a toolbar.
Select a macro.
Modify the description, caption and Icon Number.
Choose "Assign" to do the dirty work of setting up the button.

I still have to work out how to marry the code in faceIds.XLS to let the user browse face ids by image, rather than by guessing a number.

Also, please don't be deterred by the detrius within the presentation - I've left lots of code lying around so's you can play assignments with impunity. The actual USEful code is pretty small, and can be traced by following the CLICK event on the ASSIGN command button.