Suse forums seem to be a little light on the ground don't they? I use Xandros, I think the support is a lot better.
You haven't mentioned what type of modem it is, if its a Winmodem this site might help click here
The general consensus seems that Winmodems are notoriously difficult to get working on Linux and that external serial modems (hardware modems) work with any distro and forget about USB modems they just invite more trouble.
Sorry I can't be more help as I've no experience of modems on Linux.