[MC6k] 'Key Lock' issue

Hi,

I've set the param 1 & 2 rotaries to control the 'key' function instead of the filter sweep when a shift key is depressed without any issues, it's a good work round one of Denon's few oversights on this controller. However, it doesn't appear to be possible to A/B back and forth between the unpitched and re-pitched track by toggling the 'Key Lock' button as whenever Key Lock is engaged, the 'Key' rotary snaps back to a default 0 setting. I thought perhaps activating the 'soft takeover' function might help, but it doesn't seem to. Any ideas? Thanks in advance.