Hi dkilpatrick1
I've had this issue before where the vFMC does not have a Cisco serial
number from the start, so just raise a case against one of the ASA serial
numbers.
Also did you purchase the FMC support along with your ASA devices? the
product code on your bill of materials/order would start with
CON-ECMUS-VMWSW...
If you're unsure, you could try using the Cisco Case Manager live chat,
provide the serial number of one of the ASAs and ask for any details on the
support contracts. or email licensing@cisco.com.
Hope this helps
Phil