Sometimes when I want to have a more customizable volume envelope, I would use MSEG to modulate the Level of Amp Env.
I would set:
Amp Env. Attack 0, Decay 0, Sustain 100, Release 0, Level 0
In Modulation Matrix:
Source--MSEG 1, Amount--100, Destination--Amp Level
The MSEG is a short attack-decay envelope. Attack usually between 1-5ms, Decay 0-1000ms.
However, this causes distortion that sounds like noise/buzz. I tried turning the volume down on oscillator mixer, master, and Amp Level Modulation amount, but nothing works to prevent the distortion.