When you run a FvwmButtons module, you can give it a name:
Module FvwmButtons FvwmButtonsLower
The last parameter is used when looking for configuration, so you can go
on and configure the second instance independently from the first:
*FvwmButtonsLower: Fore Black
*FvwmButtonsLower: Frame 1
*FvwmButtonsLower: Back #eec090
*FvwmButtonsLower: Font
-adobe-helvetica-bold-r-*-*-12-*-*-*-*-*-*-*
*FvwmButtonsLower: Geometry +0-0
*FvwmButtonsLower: Columns 3
... etc
It's also mentioned in the man page, with the name MyButtonBox.
Hope this helps,
Jacek Kopecky