Hi Richard,  I don't have K-27 but I just converted a Bach. 3 truck shay to AirWire.  I removed all the wiring from the board that came with it added a jumper and fed the board with the AirWire head light,  that way I kept the flickering fire box,  the headlight and the cab light controlled by Airwire. I hope this helped.  ( takes some small soldering)
Allen

Hi rslater,  can't help you with K-27, but I have several 4-6-0s and 2 LGB Moguls all on AirWire and Phoenix P-5.  I took out all circuits and let AirWire control everything, works fine.  Had to change voltage on lights in some cases.  I have a 3 truck shay ( Oregon Lumber) I got for Christmas and will start this weekend to convert.  Had the P-5 programed for the 3 truck shay
sound.  Sawdust