well the script looks usefull but you really don't need a script like this to get your hair to follow the head of your character. just link it to the head bone and make sure all the verts of the head and face a weighted 100% to the head bone.
If those verts are weighted 1.0 to the head bone they will move with it exactly
as will the objects linked to the bone. dont link them AND skin them to the bone either.
Its hard to know what the problem is but if you want to upload the max scene somewhere I'd be happy to have a quick look at it for you.

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The hair doesnt seem to be the problem actually, its the eyes and mouth. Currently I've just "select and link"d them. When the head bone is rotated, they dont seem to move with the mesh properly and "sink" into the mesh, which obviously looks awful. As its a cartoony character its quite simple, the eyes are modified sphere objects and the mouth is a cylinder! I think I do want them to move with the mesh rather than the bone, if that makes sense?

Heres the scene, see what you can do!
[Link to www.yousendit.com]

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Ok, so I had a look at the scene. I never really use physique myself, I tend to prefer skin but when I had a tinker with
the file you sent I fixed the problem by ticking the "rigid" check box under active blending. basically with rigid and deformable checked
the vertices are linked to the bone and where they overlap with the next envelope they will deform. Its a bit strange, the skin modifier works much more intuitively in my opinion.
you may need to adjust the neck envelope to make sure there isnt too much overlap into the shoulders. and the eye objects are a little too thin, there not much room for error if they do sink into the mesh. personally I would probably make eye sockets and sink spheres into the head with a texture on them but thats a design choice I guess.

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OK thanks for your input. I tried ticking rigid and deformable with the head envelope (I assume thats what you mean?) and its better but the eyes still sink in if the head is rotated a good deal.

I may remodel the face slightly to have eye sockets then sink some spheres in, or at least make the eys a bit thicker.

edit - making the eyes thicker helped a lot and they look a lot better now The only real problem is that they dont properly line up with the face mesh; the nose isnt centred between the eyes when the head is rotated.

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