T39 APN won't stick

[Mike D.]

I'm trying to set up my Ericsson T39 (Unlocked) to do GPRS with 
Cingular.  I finally got through to tech support and had ISP.CINGULAR 
added to my account.

The problem is now that I can't get the APN to stick.  I keep editing 
my data accounts and setting the APN to "isp.cingular" (as per 
instructions at 
http://navasgrp.home.att.net/tech/cingular/gprs_setup.htm)

But it doesn't work.  Every time I go back to check the data account 
on the phone, my APN has been reset to the value "2".

Is this a bug in the T39 or am I doing something else wrong...