Battles ending in middle

[weby]

I really like WinSPWW2 as a game, but one thing that annoys me is the way the game often ends in middle.

A typical situation being:
My forces have managed to slow down the enemy and channel him to the killing ground.
My counter attack on sides is going well.
My artillery is keeping the enemy in place.

and then the game stops at turn 12 of 25 with a marginal victory..

I should really be allowed to play the thing to end if I wished, to see if managed to surround and destroy the enemy forces or not.

Thus my wish for a game setting that would override this behavior, forcing the game to continue past that point.