need to change path of Remote Desktop user profiles so to be stored outside of C Drive on remote host server in workgroup as it is not applied

I have a real stubborn user profile issue... for the life of me.. they will not save onto my Data (F) Drive.  I have tried changing the User Properties 'Remote Desktop Services Profile' [Profile path] to 'F:\User Profiles', I've tried various Group Policy edits as folder redirection ... but nothing seems to get these things to budge...

Any ideas, what I'm doing wrong?! :(