Ok, figured this out. You need to:
sudo cp /lib/udev/rules.d/77-mm-ericsson-mbm.rules /etc/udev/rules.d/
and then edit it to add an entry matching your card's lsusb output. That solved this for me.
Full blurb on my http://blog2.vorburger.ch/2015/03/fixed-linux-ericsson-h5321gw-3ggpshspa.html