well this works, I used the gconf thingy and it shows 5 things there (all of them having names like "AAAAA-BBBBB-CCCCC-DDDDD").

now how can I delete them? just remove the directory name of the specified APN and restart the n900 ?
I tried using rmdir, however I can't remove the directory of any of the APNs because that's not it's physical location. (like /usr/blabla)

I want to delete the GPRS settings/disable them without using other ones

I tried requesting another sms some days ago so that I could delete the old connection, but it didn't work, the new settings weren't applied/added and the old connection remained there

if I set my mode to "autoconnect to wifi" then it connects just to wifi