Unfortunately PowerShell plugin for vCO does not support CredSSP authentication.
One possible workarounds that I found on the net was to start new powershell process (using psexec) and perform the operations from there.
http://stackoverflow.com/questions/15242248/double-hop-access-to-copy-files-without-credssp
Also I found a couple of references stating that kerberos delegation could be used to resolve the double hop issue but didn't had chance to try it out.