Proxy program tracking

Hi,

I managed to get Firefox portable working in my office by entering in the proxy server number - I've only just realised that my IT dept might be able to track what programs are accessing the proxy and this could land me in real trouble.

I changed the user agent to IE6 before accessing the proxy but I didn't change the filename of the exe.

Can anyone shed any light on the chances of my IT dept flagging this up?

Thanks