Yes, the two RAID5 sets which make up the RAID50 are created automatically, in the background. They're actually handled as a single "LUN" in the RAID layer - that is to say, they're part of a single unit of storage space. Data is equally striped across both RAID 5's, so there's no real reason to display them separately unless you're interested in the potential for data loss in a scenario with disk failure.
If you had a 48-disk array (or more) and chose RAID50, there would be multiple RAID50 LUNs... But even still, those aren't exposed in an administrative view. The product is designed around taking away the need to manage things at that physical layer, and simply manage your usable capacity once things are configured.
The individual "halves" in your case can be seen with support-level commands, but it's best not to go toying with those unless you really know how to use them.