BEM

Hi Guys, I'm doing a new build with the Thermaltake Commander F6 Fan Controller. I'm using a mix of my old 3 pin fans and two 4 pin new be quiet Silent Wings 3 140mm PWM fans. I can't work out how to connect the 4 pin fan to the 3 pin connector cable on the controller. Or rather, how do I get fan monitoring with 3 pin connection if there is no fourth pin? Thanks BEM