Initializing Direct3D without a HWND

Question

Currently I'm using Direct2D for rendering 2D frames, but I realized that it's not supported in Windows XP (or anywhere with DirectX < 10), and now I'm looking for a way to support DirectX 9.

My scenario is not a simple one, and to cut to the chase my problem is that I do not have a HWND which I can use to initialize direct3d, however I do have an HDC. This is what I'm doing with direct2d:

ID2D1DCRenderTarget *renderTarget = NULL;
HRESULT hr = FACTORY->CreateDCRenderTarget(&RENDER_TARGET_PROPERTIES, &renderTarget);
renderTarget->BindDC(this->hdc, &this->viewport);
renderTarget->BeginDraw();
...

I'm looking for an equivalent thing that will work with DirectX 9 and that allows to use HDC and not HWND.

I've searched a lot, and found other question regarding this issue, but I can't find a satisfying solution, the only thing I managed to find is offscreen rendering, but I couldn't find any good source for examples or explanations about that, what I did find included the use of an HWND to initiate d3d9.

Any ideas on how I can manage to render 2D frame (with transparency) on XP? Thanks.

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Edit

WindowFromDC returns null for the HDC I pass it.
Here's my code:

HWND hwnd = WindowFromDC(hdc);

LPDIRECT3D9 d3d = Direct3DCreate9(D3D_SDK_VERSION);
LPDIRECT3DDEVICE9 d3ddev;
D3DPRESENT_PARAMETERS d3dpp;

LPD3DXSPRITE sprite;
LPDIRECT3DTEXTURE9 texture;
D3DXVECTOR3 imagepos(0, 0, 0);

ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = False;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hwnd;

if (SUCCEEDED(d3d->CreateDevice(D3DADAPTER_DEFAULT,
    D3DDEVTYPE_HAL,
    hwnd,
    D3DCREATE_SOFTWARE_VERTEXPROCESSING,
    &d3dpp,
    &d3ddev))) {

    ....
}

The hwnd is null and so the call to d3d->CreateDevice fails (I think that's the reason).
As for the HDC, it exists and when I use it with direct2d it works fine.

Any ideas how to bypass this problem?

---

2nd Edit

Thanks to @RogerRowland I've discovered that the HDC that I get is a memory HDC (OBJ_MEMDC).
I guess that it's what the browser/firebreath is giving me, but it works well when I use it with Direct2D (like in the code from my first posting) and also when I try regular Win32 rendering (with BitBlt and all).

I can't seem to find a way to use Direct3D 9 with only the HDC I get, and so I'm currently working on a workaround which creates a new hidden window in which I'll do the rendering and then will copy the result to the HDC I have (BitBlting probably).
Even if this solution works I still don't like it very much so if anyone has another approach for dealing with this problem I'd love to know.