I'm not familiar with the workings of SBS, but I imagine the steps you should take are similar to "normal" Windows Server.
What you'd ordinarily do is a system state recovery, to bring back Active Directory to a state before the crash. While your .edb files and transaction logs may be intact, Exchange stores an awful lot of configuration data in Active Directory, so by themselves the files you have aren't that helpful. It's quite possible the databases won't even mount without the correct configuration data in Active Directory.
If you don't have a recent backup, you could try starting from scratch and create a brand new empty Exchange database, dismount it, replace its .edb and transaction logs with yours and see if it mounts. If your users are all gone with the crashed server, you'll have to create new ones and reconnect the mailboxes to the appropriate users.