I haven't checked this, but I don't think you can, seeing as GF changed the HM moves for pokemon for the first time, e.g. Dive = Rock climb, Flash = Fog clear...
SO yeah, I think you can't as the invalid bytes would cause chaos in the game save. Maybe. I dunno.
Any HM moves on the Pokémon you wish to transfer have to be deleted, regardless of whether they remain as such in D/P. And yes, Flash is TM 70 now.