Nokia :: N97 Prevent Rotation Of Screen Before And During Call

How do i prevent the screen of nokia n97 to rotate and get to portrait mode when there is incoming call and during call?i on the rotation sensor so that when the phone goes horizontal the screen rotate horizontal and when it goes vertical the screen rotate vertical but screen doesn't automatically return to portrait mode if it was in landscape mode when there is an incoming call. And when i take the phone vertically to slide and answer at the same time screen trying to rotate to portrait mode and the touch screen or the phone can just freeze making me not to be able to answer the call.Is there a way to fix this issues? i've missed a lot of incoming call because of this issue. Was nokia trying to imitate the iPhone making the rotation sensor? then they should make it better by providing updates for it cause it's very irritating. Main while anyone know how to get this solve?