Animation Problem

Hi everyone.
I've imported a specific character model.

I want to reparent the child entities that make up the lower leg to the knee joint, or a pivot at the knee joint, so that if I turn the knee or the pivot, then the lower leg rotates.

EDIT: I solved a previous problem I had, but I find that the model is quite unpredictable.
Let me explain: if I turn the knee using the turnentity command, the entire lower leg AND knee rotate around the foot. This makes no sense to me since the lower leg and foot are parented to the knee, not the other way round.
Anyone have any ideas how this could be happening?

Please Help!
Thanks

Could be that the vertices are not correctly assigned. If the vertices of the lower leg are assigned to the foot instead of the knee then that will be the result. I have seen this happen before and it is always a problem of incorrect vertex assignment.

Okay, so how would I check to make sure this is the case, and more importantly, how do I correct it?

Oh, I should probably mention that the lower leg is made up of 11 different children, in case that matters.

Just load your model into an animation application and check the vertex assignment of the lower legs and reassign if necessary.
An example is Psionics Female Spy model - the vertices that make up the thighs are assigned to the knee - when you rotate the knee the whole thigh revolves around it. When animating using the stock frames this is not noticed but when you start to create custom animation you need to reassign the vertices first.