setting a waypoint

Hi,I'm trying to set a waypoint of a target in C in order to use some of the XML variables through out the coarse of a flight. I would like to use some of the variables like XML_GPS_WP_DISTANCE XML_GPS_WP_BEARING after I set the position of a waypoint. Does anyone know how to do this and set a waypoint? I know how to read XML variables using:WPdistance = aircraft_varget(XML_GPS_WP_DISTANCE,get_units_enum("enum"),0);But I need to know how to first set up a waypoint.Thanks in advance,Thomas