I own a Zune 80 player 
and have the same problem as you because the software also uses the "band" tag.
You can Synchronize what you have on your %artist% tag to the %band% one with a quick action and the following steps.
1.- Select the files you want to change
2.- Click "Actions (quick)" Button
3.- Select "Format Value"
4.- Enter The following parameters
5.- Click Ok
You can save it as an "Action Group" to have it at hand with one click.