I stared at my 930 a bit more today and I think I figured out what is supposed to block the trigger from being fired. It appears that the safety block is supposed to somehow press down on the link and push that little nubbin (on the bottom of the link, towards the end) in place to disconnect...
I didn't think think it was worth mentioning before, but after taking another fruitless stab at finding a solution I did notice something that seemed to be different for me when I install my safety. Others say that they have to lock the bolt to the rear to prevent the safety block from falling...
Alright, registered here to see if anybody might be able to help as I haven't had any luck finding answers elsewhere. I swapped the stock safety out on my 930 SPX for a metal vang one and now it will fire with the safety engaged. This is with the bolt/bolt carrier and trigger group installed...