I received your code, however I currently have no win8 dev environment therefore no chance to compile your code.
The code and the shaders seem fine, but the devil is in the details as usual.
To diagnose my problem I switched the cull mode to D3D11_CULL_NONE so the rasterizer would render everything that should be on screen.
in native c++ it would look somethin like this:
D3D11_RASTERIZER_DESC rd; ZeroMemory(&rd, sizeof(rd)); rd.CullMode = D3D11_CULL_NONE; rd.FrontCounterClockwise = false; rd.FillMode = D3D11_FILL_SOLID; device->CreateRasterizerState(&rd, &rasterizerState); immediateContext->RSSetState(rasterizerState);
Also try to disable the depthstencilbuffer as you don't need it anyway when you draw screen coordinates directly, by not setting in the OMSetRenderTargets call:
//Set the Render Context d3dContext->OMSetRenderTargets(1, renderTargetView.GetAddressOf(), nullptr)
You should also have a look at the DX11 MSDN tutorial (especially No 2), if you have not already.
I hoped I could be more helpful.
Let me know if that brought you forward.