Cannot add new Exchange Server as Target

Hello

We have two domains with a two way forest trust in place.

We both have Exchange 2010 and we both have Enterprise Vault v9.

We have done some Remote Mailbox moves from one Exchange system to the other.

I am trying to add an Exchange server from Domain A as a target in EV on Domain B.

I have managed to create the domain so i get the drop down of Exchange Server and Provisioning Group but i am unable to create the Exchange Server target.

When i attempt to create the target it errors with "Unable to connect to 'Server Name' Check that the computer is available on the network"

I can ping the exchange server so i dont understand why i cant add it via EV?

Any help would be appreciated.

Thanks