DirectX surface question

How do you fill a surface (LPDIRECTDRAWSURFACE7) with only one color? It seems like a waste of memory to create a 640x480 bitmap containing one color

Code:

DDBLTFX ddbltfx;
    ZeroMemory( &ddbltfx, sizeof(ddbltfx) );
    ddbltfx.dwSize      = sizeof(ddbltfx);
    ddbltfx.dwFillColor = dwColor;

 m_pddsBackBuffer->Blt( NULL, NULL, NULL, DDBLT_COLORFILL, &ddbltfx );

Taken directly from the MS helper classes and assumes you're using DirectDraw. dwColor is the colour (suprise, suprise). Just flip your backbuffer (m_pddsBackBuffer).

It works, thanks