How do I use an object id?

I am trying to make hitboxes work. To do this, I am modifying the cContainerRayCast (from the working gun example) function to check if a line collides with the player collision box. If I can do that, all I would then have to do is add the hitboxes on the model like collision meshes and identify them somehow so that each one can be checked for collision.

I hope that made sense...

Anyway, my problem is that I dont know how to access the Player class data from cContainerRayCast. I have no clue how I would go about doing that (I havent messed with any code this complex EVER). I have the id, obtained from this line of code (hopefully GG wont be mad for me posting this, it is only on small line):

ret = rinfo.object->getId();

The ret is the variable for return, and it is the id number of the object. I want to know how to tell if the object is a plyaer, and if so, how to call Player functions and access player data (specifically mConvex). This would be VERY helpful to me, and I will understand the engine ALOT better if somone would be so kind as to help me. Thanks alot!