When I use the kit's own sounds independent of the computer, this issue does not happen - if the foot control on my kit is anywhere between fully open or fully closed, the kick is triggered rather than the hihat sound when striking the hihat pad.
Incidentally I went to SampleTank 4 to try some kits there and found that ST was only accepting input from my keyboard, not my kit. If someone can solve that real quick let me know but I'll post in the other forum. Getting started with a new setup here.