Microsoft Jan'13 patches breaks OWA plugin

Hello all,
We are running Enterprise Vault 10.0.1, and Exchange 2010 SP2 (UR5-v2 applied)

We applied Windows patches for this month (Jan 2013) and noticed that EV buttons for OWA were gone.

We tried reinstalling OWA Extension, but that did not resolve the issue. So, we ended up uninstalling following patches from CAS server:
KB2736418 (.NET FW patch)
KB2742598 (.NET FW patch)
KB2756920 (.NET FW patch)
KB2757638 (XML Core services patch)

After uninstalling these, everything is back to normal.

My question is, what would I need to do on CAS server after applying above patches so that OWA plugin works?

Thank you,