I'm having this exact same issue.
I can only access Shared VM's via WSX if I use a local Windows account to login to WSX.
If I login with a domain account the Shared VM's are not there and I can't add the local server, the user I tested with has domain admin rights and was used to install VMWare.
I have tried starting the WSX service as another user (instead of local system) but that made no difference.
Any resolution to this?