Translate Maya shader to VRay

V-Ray V-Ray for Maya SDK
1

I am developing a plugin in Maya with custom geometry and want to render it in VRay with a Maya shader.
How can I convert a Maya shader (MObject) into VRay shader ?

Using sample provided as example:
VRayStaticGeometry* Sphere::newInstance(MaterialInterface *mtl, BSDFInterface *bsdf, int renderID, VolumetricInterface *volume, LightList *lightList, const TraceTransform &baseTM, int objectID, const tchar *userAttributes, int primaryVisibility) {
    SphereInstance *res=new SphereInstance(this, mtl, bsdf, renderID, volume, lightList, baseTM, objectID, userAttributes, primaryVisibility);
    …
}

How can I retrieve mtl, bsdf… from a Maya shader represented as MObject ?

Thanks.