Since we support ISO images on regular Data Domain, we should list ISO under Data Domain section here: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html/administration_guide/chap-storage
This bug has not been marked as blocker for oVirt 4.3.0. Since we are releasing it tomorrow, January 29th, this bug has been re-targeted to 4.3.1.
4.4.4 has been released and this wasn't re-planned for 4.4.5. Untargeting for being re-evaluated.