rapture : sustain point / sustain period

in rapture you can make a sustain point in an envelope, the point which is continously played when you hold down the key.. but is it possible to make a sustain period, like a part of the envelope which will be played over and over again when you hold down a key?

thanx! :)

-niels

ah right the loop start thing, my bad, ive been so busy reading all kinds of other sources on synthesizers the last couple of weeks id forgottten all bout the user guide :p pretty silly hehe, thanks though!!