Info from VInternals http://www.vinternals.com/2008/02/virtualcenter-25-passthrough.html
You can configure PassThrough Authentication in VC 2.5 by adding the following option to the Virtual Infrastructure Client shortcut:
-passthroughAuth -s vchostname
Very simple, very handy !!! :-)
How do you pass the user name/pw?
Hi
Your current login credentials are passed through to VC.
Gabrie