Sonar 8 Producer-Controlling VST parameters with CC envelopes

Hey everyone,
I'm wondering if there is a better way to discover the envelope assignments to control various aspects of a synth or VST.  For example, if I wanted to automate a cutoff knob within the synth I usually go to the midi track that I have assigned the synth to, create an envelope, then through trial and error try to discover what number/channel is needed to control that one parameter.  I have tried using the Write Automation feature but this does not automatically draw an envelope for me.  Is there an easier way to figure out how to assign CC envelopes?  Thanks!