Hey Achnuman,
First, welcome to the forum!!
I can tell you there's a little bit of a learning curve to get the HiHat.
First, make sure that you do the HiHat Calibration - (If you don't know what I'm talking about here, watch Hellfire's videos here
http://www.hellfiredrums.com/archives/744 (Video #3))
I also have a somewhat crazy idea that I want to try which I'll share with you here (I'll test this later on) to get the half closed hat (what I gather to be the "psst") sound..
There is a setting lug (drum key screw) at the end of the HiHat pedal. Loosen it a bit and extend the pedal to it's fullest (most open) position then re-tighten it. Now go to the DM10 and do the HiHat calibration. Once it's complete, loosen the pedal screw again and set it to halfway closed.
Let me know how this works - in theory (or at least in my demented head), it should react like a half closed hat setup.
Like I said, I'll test this out on my own kit later on.. I had a moment of coffee enlightenment