I just did a test...

In query analyzer I did a BACKUP...to...'C:\Test.Bak'

I did that command twice - putting two backups in TEST.BAK.

The first one reported in the MESSAGES pane that it processed into file 1.

The second one reported in the MESSAGES pane that it processed into file 2.

I did the RESTORE FILELISTONLY FROM DISK='C:\Test.Bak' with File=1

and also with FILE=2. I can see both backup sets in the .BAK file.

If you leave off the WITH FILE= it defaults to the first backup set in the backup file.

Now when I go into ENTERPRISE MANAGER and do all tasks->restore I notice that it really wants to RESTORE a backup made with the BACKUP in ENTERPRISE MANAGER. Those backups are made to a unique filename...

But I am able to change the RESTORE to come "from device (radio button)" and then "SELECT DEVICES...(command button)" and browse out to the .BAK file that I made.

Then back to the GENERAL tab I see that it's got a BACKUP NUMBER of 1 appearing in a text box - I can change that to 2 if I want. I can also click the "VIEW CONTENTS...(command button)" and see the two backup sets in this backup file. It's got a check box next to either file - I can select either 1 or 2 to restore from...

So it appears that EM will allow processing of a .BAK file with more than one backup set in it. Remember that all that EM is doing is running the same "t-sql scripts" that I showed you from that GUI - it's just hiding the syntax from you - but apparently all the same capability is there.