try this:I think I understand what you are asking.:
put the spring in a pair of vise grips and clamp them where they lock.
get ya a piece of soft wire and wrap it around the spring being careful not to pop the vise grips and spring.like this:
you will end up with a spring looking like this if all goes well..
now take the wrapped spring and put it in the trigger housing,long piece down towards the bottom,if the ends are the same size,then it doesn't matter.you can use the same pin,just take the pin and place the end on the anvil of your vise or a piece of metal,now take a hammer and slight tap the ends,this will do two things.1 is traighten the ends out and 2 will lengthen it so you can re-use it again.once the catch is in place and you put the pin through the holes,just reach in behind the housing and clip the wire and pull it out.