Gamo pt-85 blowback CO2 disassembally

I have gotten pretty skilled at disassembling blowback air pistols. But today I disassembled my Gamo pt-85 pistol and a spring fell off. If I had removed the spring myself I would know where to reassembled it. But now I have ended up with an extra part.

It is part #23 - trigger bar spring:


Can anyone tell me how to replace this spring? I cannot find anywhere on the trigger bar to put it...