No default route on 3G

[José Queiroz <zekkerj gmail com>]

Hi,

I'm using Kubuntu 9.10 and NetworkManager from Launchpad PPA (sorry, I
don't have the exact version number now).

The wired and wireless networks goes well, but the 3G connection
doesn't get a default route when connected.

I think that the problem isn't a bug from Network Manager, but some
residual configuration, since this notebook was originally installed
with Kubuntu 9.04 and got upgraded and updated several times.

Could someone give me some hint on where could I search these configs?