First thing is get an eight inch piece of 3/4 inch copper tubing at the local hardware store along with some JB Weld. Cut the  copper tubing in half so that you have 2 4 inch pieces. Unhook the lights and pull the wires out of the bar. You might want to tie a heavy string to the end so that you can use it to pull them back in when you are ready. Take a saw and cut two groves halfway down the end of each pipe (about 2 inches). Then cut a notch at the end of each grove. You can now use a pair of vise grips to crimp the end so that you can reduce the diameter of the pipe so it will go into the turn signal. The 2 inches you have not cut are JB welded into the light bar.
Pull the wires through and make sure you use the stock rubber boot on the turn signal to slide over the crimped copper pipe. Hook them up and you are ready to go.