Also, check out this documentation regarding DirectX and XAML interop (
http://msdn.microsoft.com/en-us/library/windows/apps/hh825871.aspx). You would use the advertising controls
in XAML, and then interop this with DirectX. You should be able to find samples for DirectX XAML interop, the main difference being that your XAML would contain an ad rather than app content.
Dan Reagan | Microsoft | Windows Developer Preview Support