VSPackage Project System Standard Editor (OpenStandardEditor) and include directories

I developing my own project system (Using MPF). My project consists of *.c files. When I produce double click on any .c file - MPF opens standard editor for c/c++ documents. For example:

#include <someheader.h>

int main()
{
return 0;
}

So - when I clicked right button on #include <someheader.h> and choosed "Open Document <someheader.h>" menu item - I got error dialog with text:

File 'someheader.h' not found in current source file's directory or in build system paths.

Current source file path: 'D:\TestSolution\test'
 Build system path: C:\Program Files\Microsoft Visual Studio 10.0\VC\include;C:\Program Files\Microsoft Visual Studio 10.0\VC\atlmfc\include;C:\Program Files\Microsoft SDKs\Windows\v7.0A\include;C:\Program Files\Microsoft SDKs\Windows\v7.0A\\include;

As we can see: search paths is used from VC++ project system props. How can I change theese search paths?