Hi fuccio
I am not quite sure if I understand the question.. I play some electronic music, and I use the built-in sequencer in my XP-60 for this. I use the 16 tracks to lay down drums and all other sounds. I usually leave out the part I want to play live, and use the sequencer to back me up.
You can also use the realtime phrase sequencing (RPS), but I haven't tried this myself as I personally like a normal (linear) sequencer better.
There should be no problem in using the sequencer in a band. Sometimes tempo may be a problem, but the XP has click out, so the drummer can hear the "speed" of the sequencer via headphones.
Hope this may have been of some help to you..
Stig