Which App store? I did have the app in development early last year for both but I don't remember ever publishing anything to either marketplace. I tested out something like you describe more recently on redmen.com, but this was about two months ago. This was through a third party software startup in Silicon Valley. A friend of mine is a Board member and invited me to test it out. But they were having a horrible time getting their act together and the reader for iPad was limited and buggy, so I removed it.
But it would be simple enough to setup an icon like you describe.
If anyone wants to "test" the DONATE link it is now in the main menu Forum>DONATE