So part of it is the SBS isn't going to be be able mount the drive as-is, so you can take the drive back, or you can run a live Linux ISO/CD, and from there you can disk partition the drive into a 2 TB (or smaller) partition, with another disk of the remainder.
all tings be equal, You might be better served to get one of the inexpensive NAS drives so that you can backup across the network, which keeps the backup physically separate from the server that is being backed up.
Example being, if a room floods, or the server is snatched, the NAS is tucked away in a phone closet or some other out-of-the-way place.
Drop some other hardware in, start the restore.
If you have some old hardware, I recommend you try out Ubuntu using the Live CD - every network can use a utility server.
