Box2d Body and User Data and colllision

Hi friends
I am creating a simple horse jumping game using cocos2d-x 2.2. I am using physic Editor to create body shape. I uses different fixture to create horse body(Like in monkey jump tutorial) and set their user data such as “leg” , “head”.
The problem is that when I am checking collision b\w horse body parts and platform by getting user data which I set in the Physic Editor. But i am getting fatal signal error.
I am unable to check the collision.

void LayerHero::PostSolve(b2Contact* contact, const b2ContactImpulse* impulse)

{
CCString *ps = static_cast<CCString*>(contact->GetFixtureB()>GetUserData);
CCString *hs = static_cast<CCString*>
>GetUserData);
if && ps~~>isEqual))
{
touch = true;
i=0;
}
else
if && ps~~>isEqual(leg)))
{
touch = true;
i=0;
}
}

Try this:
http://www.gmtdev.com/blog/2011/08/19/how-to-use-box2d-for-just-collision-detection-with-cocos2d-x/