An object that is MOVETYPE_TOSS only follows velocity while airborne. What I THINK you can do is give it a think function which removes the FL_ONGROUND flag every frame.
void() kick_think =
{
self.nextthink = time;
self.flags = self.flags - (self.flags & FL_ONGROUND);
};
You will have to code your own friction then, though. Or, if you are using DarkPlaces engine, you could just use MOVETYPE_WALK on the box.