Suggestion/Question: Position for melee attack

When I have to run to an enemy ganger to attack him, the position from where the attack will be performed is automatically chosen. But when I chose a diffrent position to run to and it costs me 4 moving points, my turn is over and I cannot attack, even when the automatically chosen position including the attack would also cost 4 moving points.
Is there a way to do that and I just haven't seen it? Otherwise it would be nice when this could be implemented.