AR Toolkit for Windows Phone 8.1

Hello,

i wonder if there is any AR Toolkit for Windows Phone 8.1 Runtime Apps out there?

It only needs to track fiducial Markers. I've already tried to use GART, but it seems like it doesn't work on Windows Phone 8.1.

I've tried that example: Tutorial

xmlns:gart="clr-namespace:GART.Controls;assembly=GART.WP8"

After i insert that Line and try to use the Namespace

<Grid x:Name="LayoutRoot"><gart:ARDisplay Name="ardisplay" AttitudeRefreshRate="50" MovementThreshold="10"></gart:ARDisplay></Grid>

the gart:ARDisplay is underlined and the Warning says: "Please make sure that the assembly that contains this type is referenced. If this type is a part of your development project, make sure that the project has been successfully built."

Hope there are other options.

Appreciate every input.