Adding an APN from the commandline

I'm in the US for 30 days and got a SIM card from Lycamobile. For some reason adding APNs doesn't work through the GUI (I add them but they never show up in the list, even after rebooting). Instead I added the following lines to my /system/etc/apns-conf.xml, just before `` Based on MCC and MNC data from Wikipedia and the information available online in general. I also enabled Data Roaming and International Roaming. I have rebooted my phone. I am on a Samsung Galaxy S3 running the latest AOKP nightly. However, I still get an R in my signal tray and cannot connect to the internet. Please advise - any help would be appreciated even if it a nudge in a new direction. Cheers, Gausie