Chromebook wireless / proxy issue

[smurfomatic]

Just opened up the first of a batch of new Chromebooks, and having a right hassle getting it online - should be easy?!

 

It has the correct wireless settings, as it'll browse our local pages (Outlook Web Access and MIS portal) but won't go online.

 

We've got two possibilities for a proxy server - our Smoothwall and the web server (which still has to handle certain applications that won't work through Smoothwall). Tried using both IP addresses as the proxy server, stillr efuses to connect.

 

Wireless network is g, WPA-TKIP but can't see why this would cause a problem if it's happy to browse locally?

 

Any ideas before I get stroppy and hurl them across the room?