PSExec remote credentials

[HippyCraig]

I have a step that uses PSExec to uninstall and install an MSI, my build machine is on a non trusted domain from the box being deployed to. Under the Advance Tab I have a user name and password for a service account that has access to the remote server and I set the options to "Use Credentials for Network Only".

If I take the same command and run it outside VB it runs fine, not sure what to do?