If RHH-135's schematic is the same as in http://www.toontrack.com/forum/tm.aspx?m=35256 then:
1. It is a high impedance pedal and must be used on the High impedance pedal input with AltIn set to Yes.
2. Sleeve is ground, Ring is for power and Tip is for signal.
3. It has only five levels of openness so is not fully variable.
4. LowLevel/HiLevel must be properly set to get it working. Starting values to play with can be set using LevelsAuto set to Yes, setting LowLevel/HighLevel to 299/300 and then pressing the pedal a few times (you may need to try different starting values for LowLevel/HiLevel instead of 299/300). After levels were automatically set, LevelsAuto must be set to No and LowLevel/HiLevel should be fine tuned.