ok,umm,youll need to get an impact driver with the correct size bit,,the rear brake lever and foot peg have to be removed to drop that cover off aswell,replace those pesky phillips(jis actually=japanese industry standard)with stainless or plated allens,,a trick to using the impact driver is to first scrape with a needle and blow out any crud from those cross heads,,they must be free from any crud and you must get a good solid bite,,you mostly only get one shot at removing these without plan B happening,, place the bit only in the screw and then knock it with a hammer,this should jar the threads a little and hopefully free them up,,then use the actual impact driver,,push it down hard into the screw and twist in the undo direction nice and square as you hit the driver with a good sized hammer.i had a dig through my photos and found a better view as to whats in there,,this is a 500 but the same arrangement for this purpose.