TIA-222-G (Draft) contains seismic analysis provisions for all of the various types of towers. For poles up to 50 ft, you can use an equivalent static lateral force procedure. Above 50 ft you must use either modal analysis (spectrum response) or a time history analysis. Enough modes should be...
STAAD does not have very good, if even adequate, cable elements, nor does RISA. They seem to use an equivalent tension only element which is not a true cable.
Check out http://www.c-conceptsinc.com for true cable behaviour for towers and guyed monopoles.