AFAIK, there is no way to "resize" any FAT partition. You have to delete both partitions and then create a new one.
I thought the CD installer came with a utility to resize FAT partitions (albeit in MS DOS)? And this isn't possible in CentOS it self? :-/
Have you looked at the gparted LiveCD?
If parted doesn't work I guess gparted won't either :-/
This is a USB drive so it's not a problem unmounting it and playing around with it.
Shame it can't be done. I thought I was finally getting somewhere with that.
Thanks again
Dan