Shading problem on skinned object

[Olli.]

this is a skinned object (an arm)
ive animated it using bones, and now im trying to render it, but it keeps getting shaded as if it was in the default pose (arms outstretched)

the picture is taken from the viewport but it happens when rendering too (tried it with scanline and mental ray)


so, any ideas on how to get the shading to be dynamic?

[Olli.]

oh and im using 3ds max 2011

previously ive used 3ds max 9 and this problem didnt occur there.