Andre - do you know wether the command Update-VmfsDatastore
does more than the steps:
1. move out all VMs
2. check if vmfs-volume is ready to unmount
3. unmount
4. run a vmkfstools command to format the already existing partition one on the LUN/disk
If thats all it does we could create a sh.script that does the same - but gives us better troubleshooting hints