Like other said.... If you do indeed have wb3.1, then you can easily read dos formatted floppies if you mount the pc0. If you have WB 3.1 installed on the HD, then you can just go into a shell and type mount pc0 and have the dos floppy inserted into the disk drive. If you do not have the OS installed on a HD, then i think you will have to copy the pc0 device from dosdrivers and onto your backuped wb3.1 startup floppy.
Remember to format the disk in 720k DD format.