What about the version 100. Is there any way to add an OpenStreetMap Layer to the map?
You can use that an interim solution (note it will not work in 3D in 100.0). For the upcoming 100.1 release we're planning to add support for several additional tiled layers (and deriving from ServiceImageTiledLayer should work in 3D too):
- BingMaps layer
- OpenStreetMap layer
- WebTiled layer (to support custom tiling schemes)
- WMTS layer