With Sporttracks v2, there is an issue that the Terraserver map plugin no longer functions correctly. Maps cannot be zoomed, and over time, none of the routemaps appear to display at all.
Thankfully, there is a user created plugin called Apply Routes.
Apply Routes provides a number of extensions to the SportTracks functionality:
The plugin for Sporttracks v2 can be downloaded here. (get the .st2plugin file).
Once the plugin is installed, selecting a different map (the blue dropdown arrow in the 'Route' window) will show the correct map underneath your activity route.