Mitel doesn't officially support SIP on the MiNET devices any longer... and it hasn't for over 10 years. Most Mitel systems include basic SIP firmware for 52xx/53xx devices only because there are some Mitel sites that still have SIP Mitel phones, but there is no longer support for other/generic devices any longer. My guess is that somewhere along the way the rest of the portal just passed into oblivion.
Could be totally wrong, but I do know SIP support for MiNet devices to non-Mitel equipment was stopped officially about 2010... knowing Mitel if likely worked for some time after that but who knows.
I've got a 5320e running 06.05.00.26 that I downloaded from Mitel today, it was running 06.05.00.11 and didn't have the Web Config, after I upgraded it the Web came alive...
