Windows 2012 RDS Desktop Background Color and Logo

Hi

I am trying (desperatly) to use a GPO to set the backround color and an image for the RDS-Users.

I tried many things (registry settings etc.) but I am only able to set a centred background image but not the background color.

However, when looking at the registry I can see the color I defined with a GPO, but it does not get displayed.

Here is the logo to be display centered:

and the background color should be 41 93 165.

By the way, it all worked on Windows 2008 R2 RDS, but not on 2012 R2 RDS, whatever I try.

Can someone please tell me how to do it on 2012?

Thanks you in advance

Thomas