Thanks for the two suggestions, but neither worked for me. I can get either panel to work fine individually, but when I add the second one in, the tabs get confused and I wind up with two of the same tabs and then two of the same subheads (just so weird, since on label is in the manifest and the other is in the properties.xml file). Perhaps someone from Adobe might have a suggestion (although xmp support at Adobe seems very limited since it's not tied to a single product).
I'll keep playing and if I have any success, I'll let you know. I would like to hear from anyone who has successfully created and is using two generic panels at the same time (I'd just like confirmation that it's possible and that I'm not just running into a limitation of the technology which only allows for one generic panel to be in use).