I had done this several years ago. As I remember all I need to do is Create a Zone with the Server HBA wwns and VSP Ports set to External.
Add VSP WWNn to LUN Masking.
Shutdown the server,
Go to UVM, highlight the VSP Ports, hit discover.
Map them to the new VSP Server Ports with Server WWNs.
Zone Server to the new VSP Ports.
Remove old Zoning.
Boot the server and it should work.
Have I forgotten anything? Or any better way evolved since the last time I did this?