I had this same question and the answer I got back from our Technical Account manager is, it should work as both pieces are ICAP, but as it is not certified Mcafee will not support it and EMC must support it.
Did you get it working? I can't get my Isilon to make a succesful connection to my AV servers.
The problem for me was windows firewall running on the ICAP servers. I added an exception for McAfee VirusScan Enterprise for Storage (C:\Program Files (x86)\McAfee\VirusScan Enterprise for Storage\VirusScanAdvancedServer.exe) and then the magic started happening