Cannot detect external hard disk as backup directory in SQL Server 2005 cluster

Hi All,

I want to backup a 1.3TB database in SQL server cluster environment. I don't have enough local disk space so I think about using an external hard disk to do the backup. However, I cannot find the external hard disk as backup destination from SQL management studio. I have tried to add a file share resource point to external hard disk but cannot bring the resource online, change the database file location to external hard disk but the disk not detected, create new backup devices as the external hard disk but no luck.

How can I use the external hard disk for backup/restore in SQL cluster environment? If it is in single SQL server scenario, can the external hard disk can be detected from SQL management studio automatically?

Thanks.