Problems with ladder climbing

So because I'm left handed I have made some rebinds on keyboard controls, one of them was to change wasd to arrow keys. Everything works perfectly except the ladder climbing. When I push the up arrow key Skif just grabs the ladder but not starts to climb, to do that I have to use W wich is very inconvenient for me. Anyone got a solution for this or am I just effed coz I'm a leftie?