How can I fix my Stihl FS55R grass trimmer?

I was moving my trimmer from a rack to a table and I caught the trigger on the edge of the table. I heard a pop and immediatly thought I had broken the trigger. The trigger was fine but a small curved piece with a Y shape on one end and a cylinder with a hole through it on the other end popped out and I can not figure out how to put it back in. It seems to have somthing to do with the spring in the trigger. Where can I get an exploded view of my FS55R trimmer. THANK YOU!