Mapping question

Hello everyone,

I have received my Midifighter just yesterday and i believe
it's a fantastic addition to my midi controller. I love the
deckalized focus AB mapping. However, I would like to make
use of FX1 in chained mode, so I could make use of the gater.

I'm not really into mapping and, if possible, I would like
a step by step instruction how to do it.

I would like it to work just the same as the beatmasher with
the same buttons. I thought about using the shift button, then
toggle the cue button on, so the light stays on, and then my beatmash
buttons change into my gater buttons.

I hope someone can help me with this.

Thanks