DirectX drawing vs. default VCL drawing

I am creating an application that uses DirectX to draw 3d and 2d shapes on
the form. The problem is: how to disable the default drawing VCL does on the
form client area. It causes annoying flickering when one scrolls the form to
the right and the VCL moves the image to the left and fills the rest with
black. How to prevent the VCL blitting the image to the new position and
instead draw the whole image with DirectDraw blitter?

Thanks in advance,
Elmo Alln