XMBEditor or equivalent for 5.00M3-6?

So for no real reason, I decided to update from 4.xx to 5.00M33-6, and in the process I lost all of my customizations saved to flash. No big deal - I'll just load up XMBEditor and put them back. No go. Not really surprising, I suppose, considering it was meant for 4.01. But now I'm at an impasse. I'd like to have my XMB wave over a background again, and I'd like to have my custom XMB and stuff, too. Is there another utility, or another way, for me to get these things back? Bear in mind that I do have the RCO files and such for the custom objects, so it's purely a matter of how.

cxmb_release33