If a Utility Partition was created during the initial install, it should be visible via the Disk Management Snap-In of the Microsoft Management Console.
Nevertheless, if your getting an error about the Utility Partition not being there, and you cannot select it in the GUI backup selection list, that go to the Text View(bring up the backup selection list and select the Text View Radio Button in the upper right-hand corner). Find the entry \\\ and delete it.
I personally never backup Utility Partitions; If I where to discover the Utility Partition had missing data, it's probably because the server is down, and I would need to reload the server before restoring the data from Veritas, so I would re-create the Utility partition from the vendor CD rather than restore it. (just my personal view).