custom captions for Powerpoint

[pw]

Greetings,

I wondered if you had any suggestions about this item. I have been creating
nice web-based rollovers using the Callouts that are available in Powerpoint
and then saving the callouts as a separate file.

Do you know if you can create your own call-outs and use them (in the same
way that you can work with the PowerPoint default call-out items? What is the
best format to save them in?

Thanks for any suggestions that you may provide.