As much as I would love the idea of a Valdemir/Ranma crossover I have to
submit the rules I was given at a "Writing in Fanfiction with Mercedes
Lackey's worlds" seminar at a convention a couple of years ago.

Legally requires the signature of a release form.  And the primary
characters CANNOT be used (ie Talia or Elsebeth).  Your unique character
can overhear them speaking to a group but you cannot make them a major
character in the story.  Also they cannot be OOC (ie Talia in an orgy or
condoning murder were the examples given).

:(

Kinda ruined the fun when I heard all that.

Sorry
Toby