Hey, give it some examples, videos or tutorials how to use this behaviors? 

Better.. 

I added my Controller to Canvas. Added a picture and give him a physical objekt, now it falls down, how i want it. But, how can I say, fall down if something before happend?

There are video tutorials and demos on the home page here - http://physicshelper.codeplex.com/

Good luck!

Thanks, I hope i will find something to get this what i want :)

Hey again,

i watched some movies and saw a lot what helps me. But I havent seen, how I could start the animation first if button x was pressed. Is it possible?

Hmm, what do I do wrong?

Sometimes it works (my objects are falling down), and most times not.

Example, i start my app, click on my ButtonX and my Object falls down. Restart my App, klick on ButtonX, nothing happend.

What I done:

1. Added physics controller in blend to my canvas

2. Added a image and give him physics object behavior

3. switched to visual studio, added following to my source

bool end = false;

PhysicsControllerMain _physicsController = new PhysicsControllerMain();

public Game()
{
    _physicsController = LayoutRoot.GetValue(PhysicsControllerMain.PhysicsControllerProperty) as PhysicsControllerMain;
}

[some other source]

private void CheckGameState()
{
    if (end == true)
    {
          _physicsController.Simulator.Gravity = new Microsoft.Xna.Framework.Vector2(0, 10);
    }
}

Hope someone can help me soon. The object dosent move anytime I want. Its not the complete game with this helper, only the end should be. Maybe someone can spent some time for me. Andy, i wrote you a message with my facebook name, maybe this will end this story faster as here. If you wish, I can sent my whole source to you.