Download the stage KMZ data of the rally you want from:
2008 year:
http://planetemarcus.free.fr/cartegoogle08.htm
2009 Year:
http://planetemarcus.free.fr/googleearthmap.htm
Next, you want, open Google Earth, choose your stage and save the track mesh.
Now, go to
http://www.gpsvisualizer.com/elevation and in choose a file section, take your KMZ stage file.
The next step is, choose the save format, (I choose GPX) and now click in Convert & Add Elelevation.
It's done! Now you need Install (If you haven't got, 3D Route Builder and click in File - Open Route and there, choose your GPX file.
Now, you will see a elevation data with a altimeter line and lot of numbers colums and data under of it.
You need press Ctrl + A for select in blue all the colums and then go to Route - Altitude - Update from Geo Tool and now, the software start to update percent by percent the altitude of GPX file to get, better and "accurate" elevation data.
When it finish, click in File tollbar and choose the Export option and save it in GPX file and then, export again but in KML file!
Now, It easy, open Piddy's BTB and import the route like open ended and All samples imoprting options