What you are doing is basically second-hopping (security delegation) to thirdmachine.
By default this feature is disabled for security reasons but can be enabled on the end point machines using the command
Enable-WSManCredSSP –Role client –DelegateComputer * Enable-WSManCredSSP –Role server
A more technical explaination can be found here: http://technet.microsoft.com/en-us/magazine/jj853299.aspx