I recently got my DX7 setup and controlling my Honeybee FP nicely, so I thought I'd post the details for all to see. I have to acknowledge John Sims, fivecheebs and pudd for pointing me in the right direction.
To fit the Spektrum receiver, read this post:
The Spektrum receiver thread
To setup the DX7 (sorry its a bit blurry and shaky - any questions just ask):
For the original thread concerning the set up of a DX6i:
The DX6i thread