Olleman, I'm surprised the crank arm is not coming off with the tool. Are you using the end cap (normally magnetic) on the end on the screw bolt part that pushes against the bottom bracket spindle ? If so is it fouling on the crank arm and you tighten the silver bolt clockwise? These normally come off simply with the tool, if anything if it wasn't budging, when you turn the silver screw bolt clockwise, it would strip the thread of the crank arm. Sorry probably not explaining myself that well, and trying not to insult you as I'm sure you know what you are doing and just have the mother of all seized crank arms