Connecting to other instances of Hyper-V Manager in domain
You probably haven't configured WMI and DCOM for remoting on your client and server. John Howard wrote a series of blog articles explaining how to connect to a non-AD integrated hyper-V server remotely and several of these steps apply to doing the same in hyper-V as well.
The simplest way to do that is to download the Hyper-V remote management configuration utility script from MSDN's code sample site and follow the instructions on John's blog.