Activating Office Trial Behind a Proxy

Hi,
I'm trying to activate the office 2007 Trial from behind a password
authenticated Proxy server, i keep getting communication error.
Microsoft help and support centre advices to activate Office 2007 by phone
for cases involving authenticated proxies. But in trial versions the option
for activating by phone is disabled.
The same problem applies to lots of corporate users , who are not able to
evaluate the product for buying decisions.
please suggest how i can continue with my evaluation.