I'm not convinced of that - I completely disagree. I don't think ASIO4ALL has anything to do with this. I use ASIO4ALL on my secondary DAW with a soundblaster! it works flawlessly. ASIO4ALL is simply a wrapper to wrap WDM drivers into ASIO driver mode in the host. it cannot affect the volume or automation of one softsynth without affecting the volume of the entire soundcard. it is not possible.
Brandon - that sounds to me like an automation problem. do you know where to find the automation? on the CSC track which isn't working correctly, click on it to highlight it, then click on your middle mouse button. that brings up the menu for the cursors. click on the pull down that currently has CLIPS selected and choose AUTOMATION>VOLUME or AUTOMATION>MUTE
each one of those will bring up a different automation line. is it set to -inf on either of those?
the next thing I'd do is insert a NEW INSTRUMENT track and then just copy the MIDI data from the first one to the new one and see if that works.
the next thing I'd check is the MIDI data itself. you can go to VIEWS>MIDI DATA
that will bring up another window and it shows the MIDI data. look for VOLUME entries in the MIDI DATA that show a value of 0.