Powering pixhawk

i have an apm 2.5 board powered by the bec esc is possible to do the same on the pixhawk or do i need to use the power module ?and if possible to power thru the esc bec can i still use the same the power switch this way ? i really prefer to use the power thru the esc bec as i am not conecting servos or nothing it keeps a cleaner build hope someone can help i want to buy the pixhawk but i dont want any surprises when in time to connect everything to the quad thanks