Ok, so I'm just going on just what I've read/seen here, but I think it's only a matter of unplugging the V2+ camera and its various grey cables and plugging in the Zen Muse in its place. You'll be left with the 2.4 Ghz transmitter sitting there uselessly in the Phantom, but you can unplug that and remove it. I don't think there's any soldering involved.
There are various projects ongoing to figure out how to use the PV2+ transmitter with other cameras. Hopefully they will bear fruit soon.