Setting up a Microphone whilst using an Allen&Heath Xone:DX Traktor Map 

With the XONE:DX .tsi map imported into Traktor, plug the Mic in, ensuring the Mic Level Control is turned down.

Set the Deck 4 Input Select Switch on the rear of the mixer (user guide page 13) to the Mic position (pressed in) then set the Traktor Deck D to Thru Mode by holding Shift then pressing the DX Mixer Channel 4 Cue/Thru button, the Cue/Thru button will now be lit by an orange LED to indicate Thru mode is enabled.  
This will disable audio from Deck D within the Traktor software until Thru Mode is disabled.

With Thru Mode enabled, raise the Mic Level Control to achieve the desired level for the mix. The channel 4 gain control is also still active so if the level from the mic is too low this can be adjusted from the channel gain control.