Capturing Overlay Screen using Opengl

Hi,
In main window, we are having Image with overlay plan above it having labeling information about that image.
We wrote the screen capture using opengl calls supported by MFC like
DescribePixelFormat
wglDescribeLayerPlane
wglMakeCurrent
DescribePixelFormat
SetPixelFormat
wglSetLayerPaletteEntries
wglRealizeLayerPalette
wglCreateLayerContext
wglMakeCurrent
wglSwapLayerBuffers
glReadBuffer
glReadPixels

It is running fine for the Image plan information but it is not able to get overlay plan information.

Any suggestions for this problem ?

Thanks,
Rohit