Lol yes i know they beamed onto a ship at warp in the movie. I just assumed nobody else would be stupid enough to try it.
NuScotty said he had successfully beamed something to one of our outer planets didn't he, several billion miles at least and that was before he had the transwarp equation? I do agree that a maximum safe distance of about 500,000km would have been a sensible limit otherwise your starships have to be in quite a low orbit or sitting right next to a ship to effect any kind transport.
I think you are right about the term 'transwarp'. I was getting confused because they were also beaming onto a ship at warp.