Set up a new ISO domain with RHEV 3.5

I'm missing something. In RHEVM 3.5 I go to the Storage tab, New Domain, select my data center. I have a choice of a few types of data domains and export domains. What happened to the ISO / NFS domain choice?

I want to move all my ISOs to a different NFS server. That's why I need a new ISO domain.

thanks

- Greg Scott