I've done this before with an Ipaq. Others have too. Details can be found at
However, on the XDA (at least my T-Mobile PPC-PE) I have not found a way to
eliminate the "+0" dialing string prefix. I suspect that this string is
somewhere in the registry. The prefix does not prevent the PPC-PE from
talking with the GPRS phone, it just seems to prevent the dialed connection
from taking place.
In the dialing settings, no country code is entered, no area code is
entered, phone number used is "*99#". Number that gets dialed is "+0 *99#".
I've tried several "Dialing location" changes, but no success.
BTW, since I know the question will arise, "Why are you doing this?" I have
only one SIM card and 2 phones (the PPC-PE and a t68i). Sometimes it's more
convenient to not have to swap the SIM card.
Thanks in advance,