[FWTools] crs definition with both +nadgrids and +towgs84 parameters

["SAEZ Laurent - CETE Méditerr./DI/ETER"]

Hi list,

Someone could tell me what appens if +nadgrids and +towgs84 are both  
used in a crs
definition (e.g. in the EPSG file) ?
Which parameter is taken into account ?
Is the behavior the same in all tools (cs2cs, ogr utilities, gdal  
utilities, mapserver,PostGIS...) ?

Best regards

Laurent