Got it to work!!!

For owners of a RTR Element RC Enduro Sendero/Trailwaler with XP100 with the Reedy 16T 5 slot motor:

Upgrading to the HW 1080WP crawler esc is a bit tricky.

To have the esc calibrate, you have to solder the motor wires correctly.
Blue wire goes to the positive terminal of the motor. (red dot on the can, next to the terminal)

Esc wire goes to channel 2 and servo goes to channel 1 (black(negative) is close to the edge of the receiver)
In you XP100 Transmiiter have your throttle trim at 12 o clock and the throttle dual rate at 100% ,
AND IMPORTANT Set your Throttle switch at "N" for normal NOT "R" for reverse.

Follow this guy's calibrating instruction