I didn't needed to remove the 3.5mm audio jack to solder the earphones, and guess what, I can now plug another earphones here. It works as a splitter!

Get ready to solder your earphones. Notice the spots where you should solder your R, L, and two G (common) wires from your earphone. I've got a couple of extra solders on the top right and left, only to figure out that those joints are active only when a 3.5mm jack is plugged in. Oh well.

Now reverse the steps to assemble the Jabra Clipper back. Please note that you'll need to cut some of the chassis' black plastic to allow space as well as let the headphone wires out. I've also cut out the top clear plastics clip shown in the previous step.