All (item #'s) correspond to the Exploded Parts View on page 11 in the Bersa Pro Series Owners Manual
How to remove the Internal Locking System (item #54):
Using the Safety key (item #53) rotate the Internal Locking System such that it is in a position between Fire and Safe on the frame.
From the opposite side push it out, being very careful not to lose the Locking System Bearing (item #55).
Once you have removed the Internal Locking System you will be able to remove the ILS Spring & Stop (item #56 & 57).
How to remove the Internal Locking System (item #54):


Using the Safety key (item #53) rotate the Internal Locking System such that it is in a position between Fire and Safe on the frame.
From the opposite side push it out, being very careful not to lose the Locking System Bearing (item #55).
Once you have removed the Internal Locking System you will be able to remove the ILS Spring & Stop (item #56 & 57).