Outlook 2010 Default font is successfully changed - users want to change it and keep their changes but each time cannot keep their changes

Hi

Using the Group Policy I have successfully changed the default font for Outlook 2010 for 1500 users. 

But a bit stuck on how do I allow them to change the default font and keep their changes. 

Each time they log out and back in again my default font for Outlook 2010 comes back into effect.

I want them to have the default font to start off with and then be able to change it and keep their changes for the whole day at least.

nicolai waldie