Bullet Engine question

[CastorX87]

Hello everyone,
Recently I've started my new small game project. During the desing I've decided to use BulletPhysics as the game's physical engine. But now I'm in a big truoble. I want to do the followings:
When two objects collide the specified sound has to be played. This depends on the material applied on the colliding trinagles of the objects. The sound sould be played (so the collision should be reported) only once (when the real collision happens, not on continous contact), depending on the impact speed and angle.
Alternatively if the above method is not possible it is also ok just to report if two "kind" of objects collide without reporting the material.
Any idea how to do this? I googled my problem and turned out that there are many methods to report object-object collision via callbacks but I can't find any correct sample code on the internet. It looks that the BulletPhysics is relly fast, but there are only a very few good tutorial. AT least I was not able to find one I need to do this. If anyone knows how to do that or has a link to a good tutorial please help. Thanks in advance!

[KroArtem]

Supertuxkart developers use bullet for physics and they had some problems how to define collisions of karts. Probably you can ask them (preferrably hiker)