That 90 degree angle should match up to a hole in the trailing arm.
There should have been an included bolt, washer and nut set for both sides.
The L shape that I was reffering to was the trailing arm, not the 90 degree angle.
Just bolt up the 90 degree to the side of the trailing arm.
Once it is bolted up you should be able to connect the rest of the sway bar with the included long bolt and bushings.
There wasn't a tube spacer in my kit.
I think that you may need it (the tube spacer) to stop any rattling noise.
Oh yeah it's not the control arm in the rear.
Here are those pics that I promised. You won't have to wait until Saturday. They are bright and it's really dirty, but I believe you can make out enogh detail.

Good luck.