I don't have a complete answer. What I know is you can add any control to a map using this technique:
myMap.Layers.Add(new MapLayer()
{
new MapOverlay()
{
GeoCoordinate = new GeoCoordinate(37.795032,-122.394927),
Content = new Ellipse
{
Fill = new SolidColorBrush(Colors.Red),
Width = 40,
Height = 40
}
}});
This comes from http://developer.nokia.com/Community/Wiki/What's_new_in_Windows_Phone_8
Now this will display a simple red dot, but I understand you can put just about any control in there. Use your control, bind the rotation to a value that will hold the rotation in your view model and I think you are quite done. Does this work for you?