Hello Niko,
there's already people who have reverse engineered those Nt* structures in detail, but I'm not sure if we're allowed to use them.
Alexandre said that we can't use ReactOS code because "A lot of it was reverse-engineered using methods that are not appropriate for Wine" but I don't think those other resources like like geoffchappell.com are created a different way.
Regards, Fabian Maurer