Windows Phone 7 - GeoCoordinate.Speed at emulator

When testing GeoCoordinate Class (http://msdn.microsoft.com/en-us/library/system.device.location.geocoordinate.aspx?wa=wsignin1.0) find that Lovacation.Speed property on emulator return NaN value (latitude, longitude works).

Also test MS sample - http://create.msdn.com/en-US/education/catalog/sample/geolocation (also NaN value fo开发者_如何学Gor speed).

What is the best way to emulate\test speed in emulator?

The basis idea is to create an own implementation for IGeoPositionWatcher. On SharpGis you find one which generates random data from a starting point and calculate the speed based on the traveled distance. Alternatively if you have a GPX document you can create an implentation which returns the data from the GPX file.