ok, at the rear of the brake, you can adjust it a bit.
at the brakelight switch you have a bolt with 2 nuts.
step 1: loosen the lower one.
step 2: adjust the upper nut, you'll see that the brake-peg is moving (up/down depends on which way you're turning)
step 3: when in desired position, tighten the lower nut again.
dubbelcheck: you can not lower the brake that much, you still need some movement space for the brake-light switch and brake before they engage.
so unless you adjust the brake-switch too, you're brakelight and brake will be on all the time.
other option is to buy another brake-peg
hope this helps