Wang Controls

Hi,
I have a UMAX scanner and I am rtying to scan an image using the Wang controls. If I do not set the ShowSetupBeforeScan to True, I am getting the Image's Negative (ie Black in place of white and white in place of Black).
But if I set ShowSetupBeforeScan true and give the start scan from the window it shows (when ShowSetupBeforeScan is set to True) it gives me the correct image.
Please send me if u know any solution for this problem.
Thanks in advance
Arjun

Software Engineer
Bangalore