Hi.. Just tried the mapping again and i am not making this expirience. I use Traktor 2.11.0 23 and re-uploaded the *.tsi file i just used. The mapping was imported via the controller manager menu, i hope that can help..

Of cause once the step sequencer is active, all the remix deck controls are not working any more, since it transformed to the step sequencer. Also the volume for each slot doesnt work in step sequencer mode because it is not mappable or at least i couldnt figure out how to do so. So the main controls left are the modifiers on the upper "FX4" to see the steps running or setting your samples (e.g. M8=0/M8=4 for Slot 1 = "On/Sel" Button FX4). Plus the functions "Selected Samples", "Pattern Length", "Swing" and "Sample Page" on the encoders from left to right in that order.

Hope that works.