automatic start script on pendrive

Question

I would like them to start a backup with rsync (type: rsync --delete -av /media/xxx/yyy /media/aaa/bbb) about 10 seconds after inserting a certain pen-drive (recognizable by VID and PID). I followed this post that makes me mount (and unmount) my pen-drive regularly which is read automatically (VID and PID) but I can't launch, after mounting, a script to start rsync... Thanks for any helpful advice.