The 2 wires that are soldered to the LED board are what holds the whole thing together. I used a spring-loaded solder vacuum to clean those 2 connections out to get it free. Note which side is positive when taking apart as there is no indicator on the board. The LED board is epoxied to the head, a lighter or small torch will get it hot enough to ruin the adhesive and it comes off easy. Careful with the hot head. I couldn't think of a way to use a different LED board so I just floated off the old and put a new one on.
Patience and a steady hand will help as will slowly approaching the melting point so as to not overheat things.
I recommend using epoxy for re-applying the board as you don't want those leads coming up from the control board to bump up against the side of the hole they go through from the twisting that will occur every time you change the battery, they may eventually short circuit.
edit: I used the same form factor emitter. YOu may have different issues with the smaller xpg-r5.