// set-up the virtual table
final GSVirtualTableEncoder vte = new GSVirtualTableEncoder();
vte.setName(nativeName);
vte.setSql(sql);
vte.addVirtualTableGeometry(vtGeom);
vte.addVirtualTableParameter(vtParam1);
vte.addVirtualTableParameter(vtParam2);
// modif the vte
vte.delVirtualTableGeometry("the_geom");
vte.addVirtualTableGeometry("the_geom", "MultiPolygon", "4326");