A. SQL doesn't have tape loader support, so it will only use the first tape in a device.
You can use tape loaders with SQL Server by buying one of the 3rd party backup tools that work with SQL Server agents. These do dumps from SQL Server via named-pipes (6.5) or VDI (7.0) and then utilise their own drivers for device support.
Examples are :-
BEI Ultrabac www.ultrabac.com
Cheyenne Arcserve www.cheyenne.com
Backup Exec www.seagatesoftware.com