Desk Top Upgrade

We have up 70 virtual machines that have been provisioned as persistant disks.

These are perminant desk tops that are designed using a one to one relationship with their AD user.

These images are tied to the AD account and have a number of personalised settings including favourites shortcuts, outlook profiles etc. my client is planning to upgrade to 7.6 from 6.2 and deploy windows 7 with office 2010 using the new version.

Is thre an upgrade path (of the users persistant disks not vworkspace) that i could implement so that all of the remaining machines are upgraded to windows 7/office 2010 with out losing all of the personised setting?

At the same time as upgrading the virtual machines we also require that extra memory is distibuted to the VDI and increase the disk space from 20 GB to 50 GB.

Your feed back is much appreciated

Regards