T48G not re-registering with server automatically

[mattnotley2005]

I am using a T48G running the latest firmware (35.80.0.70) but when changing the "Server Expires" value to something smaller than 3600 (default) it doesn't make any difference. The phone re-registers after 3600 seconds based on my SIP providers expiration time, not the shorter value I specifed on the T48G.

I have the Bria softphone app on my iPhone which I sometimes use in-place of the T48G. When exiting this app, it results in the SIP number being unavailable. I want to make my T48G re-register after 180 seconds so calls can start going to the phone shortly after exiting the Bria app. However, due to the "Server Expires" value not working - I have to wait anywhere up to 3600 seconds for my provider to renew expiration unless I manually restart the phone.

My SIP provider definitely allows 180 second re-register values (this has been tested using Bria), just doesn't seem to work on the T48G.

Is this a bug? I have been experimenting for a few hours, but can't seem to get it working.