While the comgt workaround does not seem to work anymore on 12.04, deactivating the PIN on my SIM card did the trick this time. After turning off the PIN and attaching the modem, it takes network manager a few seconds to find the new interface. I can then select "Enable Mobile Broadband" and connect to a mobile 3G network, however.
Not sure what the problem here is, as SIM cards with PINs used to work fine on Lucid and Maverick (and Natty, I believe). But for now at least we have another workaround :-)
While the comgt workaround does not seem to work anymore on 12.04, deactivating the PIN on my SIM card did the trick this time. After turning off the PIN and attaching the modem, it takes network manager a few seconds to find the new interface. I can then select "Enable Mobile Broadband" and connect to a mobile 3G network, however.
Not sure what the problem here is, as SIM cards with PINs used to work fine on Lucid and Maverick (and Natty, I believe). But for now at least we have another workaround :-)