function BesselToWGS84(lon, lat)
{
   var coord = m_Map.GetCoordSys();
   var pos = coord.BesselToWGS84(lon, lat);
   alert(pos.GetLon()+"-"+pos.GetLat());
}

#include "CXCoordSys.h"
#include "CXMapPos.h"

CXMapPos CSampleDlg::BesselToWGS84(double Lon, double Lat) 
{
   CXCoordSys coord = m_Map.GetCoordSys();
   CXMapPos pos = coord.BesselToWGS84(Lon, Lat);
   return pos;
}