Secure WIFI login issues with iPhone

My work has a secure WIFI network that requires you to enter a username and password at a splashpage. Before iPhone OS 3.0 it used to send me to this spash page every time i entered the WIFI area.

Now, with the 3.0 OS update, it has the auto login feature. But everytime i lock my phone, it seems to forget the Wifi signal and i have to endure the auto login issue each time i unlock the phone.

That is, EVEN if i it'll log into the system. It's sorta annoying. Am i doing anything wrong? I'd like it to remember and keep logged into WIFI while i'm in the building and not keep forgetting and having to re-log in every single time i lock my phone.

What am i doing wrong? I'm using OS version 3.0.1 (in order to keep my teathering still working)

 

Then why was i not having this issue before? Did they change this in the new 3.0 firmware?