I've done this in the past; not cloud hosted per se, but with other VM environments; from what I remember you have to set the vm serial number somehow so device enrollment will work; it also helps helps to set the model identifier:
In the form of:
devices.smbios.serial=""
devices.mac_hw_model="MacPro7,1"
added to the .vmx file of VMware. ; When I do this, I'll usually remove two letters from the host serial; and replace them with VM, etc. Hope that helps
