@acadia: I am afraid so, but it would do away with the advantage and be as cumbersome as transmapped hair. I have not given up the hope yet!

@EnglishBob: That may be an idea. Spawn Morph Target will not work I am afraid, but I do not know whether dynamic hair would be exported in a .obj an could be read as a morph target.

@CaptainMARC: That is another good idea; thank you; will try this and revert.

@RedPhantom: Cage's bake Deformation script. I do not know that one, but if it does what the name suggests it may be useful. Will sort that out.

@MysticEagle: That is plan B indeed. It would work for closed and non-transparant hats only, and I would need to work out the hair style!. Thank you anyway. 

Thank you all for your responses. you gave me some good ideas. Will revert on this. (Need to do something these days ;-) )