I'm not sure how you're putting in your interfaces.
I run multiple virtual interfaces on openSuse, and got them there through yast config.
Network devices -> Network card -> (select card) -> configure -> from here you can "add" additional addresses
Mine don't get lost on reboot (I figure you must be doing it a harder way than you need to, and it's probably the wrong way to do it on suse -- use yast in preference to config files.)
Last edited by secesh; 11-20-2008 at 08:12 AM.