finding slope and adjusting pitch and roll.

Do any of you know if it is possible, and if so how, to find the slope of the terrain at a point on a hill and to set the pitch and roll of a unit standing there so that he is standing perpendicular to the terrain instead of standing straight up and down even on slanted terrain. if you don't udnerstand look at this:

There's no way to set a unit's pitch and roll dynamicaly that I know of. However, with sufficient max pitch/roll angle values, the unit should auto-adjust to any cliff.