1.8 Mk2 Carb problem

Hi all,

I have a 1.8 Mk2 golf that I've just replaced the carburettor on (pierburg 2E2). Unfortunately, as I removed the old one a pipe/tube at the back of the carb fell off and I don't know where it goes. It is one of a pair, one of which goes to the 'three/four point unit'. Does anyone know where the other goes? I've looked at the haynes manual but it doesn't explain the connections well enough.

Thanks
Graham