Comment 1 for bug 1271868

I am having the same issue. I have done my remapped in a slightly different way, substituting the relevant lines in
/usr/share/X11/xkb/symbols/br (I use a Brazilian layout) for

key <AC07> { [ h, H, Left, Left ] };
key <AB03> { [ j, J, Down, Down ] };
key <AB04> { [ k, K, Up, Up ] };
key <AD10> { [ l, L, Right, Right ] };
key <SPCE> { [ space, space, Right, Right ] };

Outside of Unity dash, AltGr+H/J/K/L gives me the arrows keys.