DDJ-1000 - How to set my headphones as master output

I recently bought my DDJ-1000 and I have some trouble to set the Audio Preferences correctly. My speakers are connected with an RCA cable on Master 2 output channel of my controller, so I set Master Output on "DDJ-1000 ASIO : MASTER" in the preferences and the music is playing correctly out of my speakers.

However, sometimes I like to mix with only my headphones on. On my old controller with Serato, I used to just turn the headphones mixing knob between Master and Cue, but now I can't find how to set the audio preferences in rekordbox if I want to mix using my headphones for both Master AND Cue.

Can someone help me on how to set my preferences correctly? Thanks!