LLVM/Clang 3.1: Add a new include path in a clang C++ based parser

Hi,

I'm having troubles to add a custom include path to a clang based C++ parser.
I'd like to properly support this opencv code under Linux:

...
#include "cv.h"
#include "highgui.h"
...

This is what I'm using:

TheCompInst->getHeaderSearchOpts().AddPath(StringRef("/usr/include/opencv"),clang::frontend::Quoted ,false, true, false, false, false);

Note: I have tried also with clang::frontend::Angled without success.
Can you see the problem? Could you please say me where can I find some Clang 3.1 based related example?

Many thanks in advance.

This is a more extended captured of how I am using "AddPath".
...
     CompilerInstance *TheCompInst = new CompilerInstance();
  TheCompInst->getHeaderSearchOpts().AddPath(StringRef("/usr/include/opencv"),clang::frontend::Quoted ,false, true, false, false, false);
     TheCompInst->createDiagnostics(0, 0);

     TargetOptions TO;
     TO.Triple = llvm::sys::getDefaultTargetTriple();
     TargetInfo *TI = TargetInfo::CreateTargetInfo(TheCompInst->getDiagnostics(), TO);
     TheCompInst->setTarget(TI);

     TheCompInst->createFileManager();
     FileManager &FileMgr = TheCompInst->getFileManager();
     TheCompInst->createSourceManager(FileMgr);
     SourceManager &SourceMgr = TheCompInst->getSourceManager();

     TheCompInst->createPreprocessor();
     TheCompInst->createASTContext();

     Rewriter TheRewriter;
     TheRewriter.setSourceMgr(SourceMgr, TheCompInst->getLangOpts());
...