How to make my toolbox app appear on top of a Direct3D surface in both Window mode* and Full screen?

I've been working on a toolbox like application for one of my favourite games...

* In window mode it needs to be able to 'stick' to the bounds of the window like a wart plaster, I've been using 'TopMost=true' to make my toolbox appear on top - though, but I can't seem to find a way to lock it to the bounds of the games' window.

I can't get the toolbox app to show above the Fullscreen Direct3D game, which seems to be intended behavior, unless there's a way around it, Though I've been reading about DirectX hooking in C++ and it seems possible with that, though I know next to nothing about C++, My skills lie in C#, Java and VB.NET.

Tools like Fraps and Xfire seem to be able to do this no problem...

At the moment it's eluding me, since all the samples I've tried have either not worked or not worked as intended, or just plain wrong.

Note: I do not have access to the games source code, nor do I want it ;)

Note: Microsoft in their infinite wisdom have given me the run-around on this for the last 3 years, directing me from forum to forum to forum, I'd like some closure on this....

The only way to do this is DirectX hooking with C/C++. This kind of problem could not solve with a managed language. And yes it is pretty complicated and you risk to be banned on games with strict rules about cheating. 

Ralf Kornmann:

The only way to do this is DirectX hooking with C/C++. This kind of problem could not solve with a managed language. And yes it is pretty complicated and you risk to be banned on games with strict rules about cheating. 

In my case, I'm not trying to do it to get any kind of edge. Besides I've obtained permission from the developer - so long as I stay within certain conditions and make no attempt to actually edit the game files.

I'm fighting with a similar problem at the moment.

What I have done is write a proxy dll which intercepts all d3d9 calls.

In the present call I add my stuff.

I am having massive problems myself with the way that d3d9 uses surfaces and textures, which just seems to be designed purely from a system architecture viewpoint with absolutely no thought to useability, but I think it is the only way you can go.

The only tutorials on this subject I can find are 3/4+ years old and don't seem to work on latest versions of DirectX runtimes/SDKs. Which means that I have come once again to a dead end :(

Trying to work around it, If the guy who wrote a similar one for the previous version of Entropia Universe shared his code, I wouldn't need to reinvent the wheel... too much...