Cleaning the "Portafiltro"

If anyone has successfully reassembled the portafiltro, do you know where the tiny spring is meant to go. I can guess that it's meant to push back the small oddly shaped cam that raises and lowers the coffee port cleaner, but can't find the way to seat it. (the machine appears to work perfectly without the spring though, though...

Its not the larger round spring but the tiny whiskery thing.