Please help a noob :(

Panther91

Dear programmers,
I'm new in c++ builder 6.0. I have a form with a vertical scroll bar. Also I add in the form a PrintDialog. But when I execute the print button,the output of the printer is the image that shown on screen(not the full document).For example my total document height size is 1000 pxl. My form has the height size 700.So if the position of Scroll Bar is 0, I will print just first 700 pxl,not 1000...What should I do?
Waiting your promptly answers thank you.