I think you could probably do this. If you have a persistent disk you can test with then try the steps below.
1: Archive persistent disk on 4.5 environment (this will delete the VM it is associated with)
2: Once it is archived delete it from the View connection broker only (DO NOT DELTE FROM Disk)
3: Go into the new 5.0 environment and go to your persistent disk tab.
5: use the import from vCenter option to browse out to the datastore where the archived persistent disk lives and import it into the 5.0 environment.
6: associate it with a dedicated linked clone pool
7: recreate desktop with persistent disk.