MS Office Project 2007 Macro Security level using GPO

Hi,
Could someone please explain to me how I can set the macro security level for Office Project 2007 using a GPO, that the user can not change?

I?ve got the Office 2007 ADM template files and imported them. However the template is only for User Configuration and not Computer Configuration. This means I can set the security level but a user and can easily change it to what ever they want.

Im using AD 2003

Thanks
Tom