This should be added to the code:
D3DXMatrixTranslation(&matTranslate, 0, (float)clientRect.bottom, 0.0f);
D3DXMatrixRotationX(&matFlip, D3DXToRadian(180));
D3DXMATRIX matCoordTransform = matFlip * matTranslate;
g_pDirect3D_Device->SetTransform(D3DTS_WORLD, &matCoordTransform);