I find it hard to believe that this hasn't come up before. Oh well, I'll just have to figuire it out for myself. 
1. slide the straw over the spring retaining wire , all the way to the end of the wire, it should fit snuggly.

2. slide the recoil spring all the way in.

3. place the rear end of the top cover firmly on the table (preferrably on a non-skid pad or the wife will kill ya, lol) and using both hands grab the spring and push it down till it passes the top of the retaining wire(you can see it thru the straw). taking the next two pic was no easy task due to the pressure from the spring, luckily i kept it steady and it didnt fly away.


4. hold the spring firmly with your fingers (thumb, index ) while the remaining fingers (middle, ring and pinky) gripping the top cover, once that is done, release the other hand and pull up the straw, exposing the top of the wire.

5. with the free hand put the spring retainer piece on top of the wire to lock the spring in, easy way is to line up the two wire with the grooves on the side of the retainer piece and rotate the piece with your fingers and the wire will line up to locking position... note my fingers was turning purple due to it took longer than a minute to take pics.
