It would be trivial to reformat the UUID without spaces and hyphens via Perl (of if you're using the CLI tools, awk/sed/powercli, etc).  Is there something more complicated with your UUID format in your CMDB? 

You could also generate your own UUID values with an appropriate library, then add them into the VMX settings of the VirtualMachines during creation time.  Then you'd have UUIDs in the format you prefer.