Error connecting to vCenter server in virtual appliance and AMS

We are currently running ABR10 Virtual Edition and using virtual appliances to image a number of virtual guests on two ESX 4.1 hosts which are managed through a vCenter 4.1 server. We have implemented a new ESX 5 environment which is managed using vCenter 5.0 and need to move the ESX 4.1 hosts so they are managed using the same v5 vCenter. I have moved the hosts to the new vCenter and can manage them from a VMware viewpoint without any problems, but if I try to reconfigure the Acronis virtual appliances to connect to the v5 vCenter I keep getting an error saying they are unable to connect to the server (see attachment 1). Similarly if I try and change the vCenter integration option in the ABR10 management server to connect to the new v5 vCenter, I get an error (attachment 2). I have tried searching for any information on whether the new version of vCenter is supported, and if this is the problem, but can only find info on supported versions of ESX which, as it hasn't changed on the hosts concerned, cannot be the issue.

For reference, we are running ABR 10 Update 5 Build 10.0.1.13762 and the two vCenter versions are 4.1.0 Build 345043 and 5.0.0 Build 623373.

Any help would be greatly appreciated.