Greg -= that's not correct with MC6.
to create an envelope in MC6 you need to use the SMART tool. Use your CENTER mouse button (click down on the wheel) and the Heads Up Display for the Smart Tool will appear. on the pull down menu in the HUD (it currently will say CLIPS), choose AUTOMATION>VOLUME
a volume envelope will appear on the track. make your adjustments, then use the HUD Smart Tool to go back to CLIPS