iTunes with Windows folder redirection

Hi all, several of the users at my company use iTunes on their Windows machines. We have folder redirection for "My Documents," and when they are off the network, they can't access iTunes and get the error 'The folder "iTunes" cannot be found or created, and is required. The default location for this folder is inside the "My Music" folder.'

My question is, how do I change the location of the "iTunes" folder for already installed configurations and how to do it for new installations as well.

Thanks!