Converting SFM rig to Blender rig

I am currently learning to use Blender after using Source Filmmaker for some time. I have come so far as to import an SFM model into Blender, apply texture to it and now I have gotten to the rigging/animation part. The model I use came with a “built in” rig, which I would really like to continue using and expand on.

I have tried to delete the built in rig and make a new Human (meta rig) after following a tutorial. This works fine and I get the rings that I use to move the limbs around. Problem it, I don’t have these rings on the built in rig. I am also missing the “Rig Main Properties” tab where I can change the FK/IK sliders.

So my question is - can I somehow convert the built in rig into a rig that lets me use Blenders FK/IK sliders and options like the meta rig has? Here is a picture of the model with the built in rig selected if it helps: http://i.imgur.com/AH5qo0L.jpg

Any help it appreciated! :slight_smile: