ok, now I feel like an idiot…
firefly couldn’t find the files because my samba config made the directories created by itunes inaccessible for it… duh! (why couldn’t I think of this 10 minutes earlier…?)
But anyway, found another minor thing: .mov files are not listed as video files, but as audio (no video icon, only audio playback when playing). If I rename the file to .m4v, it plays nicely (just tried it with some HD trailers off Apples site). Also, I think I read in these forums somewhere that video streaming copies the complete file to the iTunes client before playing, but this seems not be the case with the Apple trailers – the video starts pretty much instantly.
thanks anyway, mike