I don't profess to know where the regression lies, but my suspicion would be with ModemManager. (It's easy enough to test anyway). Try downgrading the ModemManager package to the openSUSE 12.1 version.
On a Dell Latitude 6320, using opensuse 12.1 64 bit, this card normally asks for its PIN, as soon as I log into KDE. I can then use the networkmanager to make a UMTS/EDGE/GPRS connection. With opensuse 12.2, the PIN is never requested, and I am also unable to activate "enable mobile broadband".
and select 'Show other versions'. Download the required package.
As a quick test, I downloaded the 12.1 version and the following 'dry-run' indicated no package conflict issues
You'll need to restart the network manager
# zypper in --dry-run --force ModemManager-0.5-3.1.3.x86_64.rpm
Loading repository data...
Reading installed packages...
Forcing installation of 'ModemManager-0.5-3.1.3.x86_64' from repository 'Plain RPM files cache'.
Resolving package dependencies...
The following package is going to be downgraded:
1 package to downgrade.
Overall download size: 220.0 KiB. After the operation, 130.9 KiB will be freed.
Continue? [y/n/?] (y): y
then proceed to testing you broadband connection.
Does it then behave as it did with your 12.1 install?