Does anyone know how to resize the user disk once a VM has been created? I have not tried a recompose because I am not sure what would happen although the User Disk should not be impacted as it only deals with the system. Is this a case where you need to destroy the virtual machine and user disk combo and start over? That would not be a good thing.
Here is a trick that might work..
1) Shutdown the VM (VM1). Make a not of VMFS volume that the virtual disk is on
2) Remove the disk from VM1.. "Do not delete from disk"
3) On another shutdown VM (VM2) "add" a new hard disk, select existing disk and locate the user disk you removed from original VM1. Assign higher SCSI ID than 0,0 (eg 0,2)
4) Increase the size of required virtual disk in settings of VM2
5) Boot the VM2. Goto command prompt and type DISKPART. Follow this article to extend into new space ()
6) Shutdown VM2 > Remove the disk you just exteneded > Goto VM1 and add hard disk back "use existing" and select the extended disk (SCSI 0,0 if its and OS volume you want to boot from)
This should hopefully be what your looking for