I have played around with MS samples of this(http://msdn.microsoft.com/en-us/library/windows/desktop/dd371004(v=vs.85).aspx) and they work fine on my win7 install.
However when I try to mimic their setup for my own work, I get this message through the debug output right after I call EndDraw with the D2D render target:
D3D11 INFO: ID3D11DeviceContext::OfferResources: OfferResources is not supported on operating systems older than Windows 8. It is valid to call OfferResources, and an offerred resource must still be acquired with ReclaimResources before using it, however there is no benefit to calling OfferResources on this operating system besides testing the code path for Windows 8. [ EXECUTION INFO #3146071: OFFERRELEASE_NOT_SUPPORTED]
and the end result is that I get a blank screen. It makes no sense because I am using D3D10_1 not D3D11.