Exposing third-party API to QtScript

[hipersayan_x]

Hello, Im working in a proyect where some plugin capabilities are need, because I need this plugins to be multiplataform, then I desired to try out making this with QtScript.
One of the API's I want to expose is OpenSceneGraph, then my plugins developers, can render advanced 3D scenes without worry about plataform issues.
But I stuck because can't figure out how to convert from a OSG type to a QtScriptValue and viceversa.
For example, I want to expose "osgDB::readNodeFile()":http://www.openscenegraph.org/documentation/OpenSceneGraphReferenceDocs/a01557.html#177e1656d3766fcab9e38c7681fb94b3, It's form is:

@osg::Node* osgDB::readNodeFile(const std::string &filename;, const ReaderWriter::Options *options)@

Then create the wrapper funcion as show in:

http://doc.qt.nokia.com/latest/qscriptengine.html#newFunction

@// Create the wrapper funtion.
static QScriptValue osgDB_readNodeFile(QScriptContext *context, QScriptEngine *engine)
{
// Obtains the arguments from QtScript.
QScriptValue filename = context->argument(0):
QScriptValue options = context->argument(1):

// Here is my first question, ¿How I can convert from QScriptValue to a OSG type?
osg::Node *retval = osgDB::readNodeFile(filename.toString().constData(), optionsretval.toOSG());

//And second, ¿How I can convert from a OSG type to QScriptValue?
return toQtScript(retval);

}@

Of course, a second (and more easy) option is to distribute the plugins as source code, and making it binary by compiling at install time, but I think the first option is more correct.
Some clue about this problem will be appreciated.