thats utter cods mate. i used to run a paint shop and i painted no end of shadow chrome wheels. the reason why they cant do it is cos they dont know how to.
This is how you do it. it's ideal to paint 2 wheels on the same side of the car for any slight colour indescretions. Prep your wheels and once they have been primed you have to paint them black using any black basecoat.
Then you need to get hold of some MIPA SPARKLEGLASS. this is the name of this chrome paint. might set you back around £80 ish but you need it. then you spray 1 good wet coat straight out of the tin, but you might need to re apply another coat dependent on the darkness of the wheel effect you want.
Once you have done that laquer thm and thats about it.