Ok, this works...
Manually update your VCA's to 7.3.0.0 and they can then talk to the VCRM.
However, according to another thread here (http://h30499.www3.hp.com/t5/ITRC-HP-Systems-Insight-Manager/HP-Version-Control-issues-after-upgrade-from-version-7-2-2-0-to/td-p/6319379#.Ut02qPRFDyM), this new version has issues with firmware and BIOS updates not being shown.