Edit: Derp, didn't read both your posts. When you reconnected the trigger bar it probably just pushed the spring down far enough to have that little tab hook onto the trigger housing.
I don't have much experience with the NY springs, but I did just complete the Armorer's Course and we got to install the NY springs. The particular gun I got to work with was a gen 3, so I'm not 100% sure the gen 4 will yield the same results but...
If you look at the back end of the trigger housing, the NY spring should have a little tab that "hooks" onto the trigger housing which kinda locks it in place.
Last edited by UnbrakableX; 01-16-2013 at 15:43..