How can I correct an airport's position ?

Hi,It has now become part of my flights preparation to load the SRTM DEM data along my flight path, and to process them to .bgl files, using FSDEM 1.1, available here at AVSIM. I encountered several times the problem of runways in deep trenches, or on elevated plateaus. I finally succeeded to correct these problems by adjusting the airport altitude with JABbgl (also available here), and flattening the terrain with Steve Greenwood