CGull

Magog, (sadly) I fear I am not able to help then. The only thing I wonder is what language your keyboard is set for, and is it different than US English (which is what mine is set for), if that would affect your setup making the results (or lack thereof) different than mine?

Assuming that you are on Windows (because you mentioned "alt.") On my Windows machine, I can do ALT + LMB + RMB and then drag up or down to make a brush softer or harder respectively, and I can drag left or right to make the brush smaller or larger respectively. On a semi related note, if I press SPACE + CTRL (in this order) and then drag left or right I can zoom out or in on the canvas.