Thanks!
before I saw your post I tried just using FAT32, having to convert 3 test VMs into "split-up" vmdks.
When I started one OpenSUSE Linux it came up, and as I saw the login screen Workstation told me there are some operations not possible.
The VM went black and nothing happend. When I tried to re-start it, it said "no files found", and in the Explorer really the whole Disk was gone.
Windows didn't even see it anymore in the Disk Utility...
I tried rebooting and it recognized the Harddrive again. After that I added your line to that Linux and another Windows XP VM and both went smothly.
Just for a test I shut them down, deleted them from Workstation, removed the line and started both of them again. No problems.
So I wonder what happend when I first tried Linux on Fat32 (the crash), but what ever it was, with FAT32 it seems to be working good enough (with or without that line).
So maybe I'm gonna combine the two approaches: One Partition FAT32 for the VMs with split up vmdks, and one exFAT for the rest with bigger files.