DURING AN IFR ARRIVAL, AN ILS APCH WAS MADE TO RWY 29 IN RAIN, TURBULENCE & GUSTY WINGS. AT APRX 400 FT AGL, THE ACFT BROKE OUT OF THE CLOUDS WHILE ON THE LOCALIZER GLIDE SLOPE. THE AIRSPEED AT THAT TIME WAS 8 KTS ABOVE THE REFERENCE SPEED, BUT WAS FLUCTUATING DUE TO THE TURBULENCE. THE PLT REPORT THAT JUST BEFORE TOUCHDOWN, THE ACFT SETTLED & PARTIAL POWER WAS APPLIED; HOWEVER, THE PLANE TOUCHED DOWN ON SOFT, WET TURF APRX 20 FT SHORT OF THE RWY LIP. IMMEDIATELY AFTER GROUND CONTACT, A JOLT WAS FELT & THE ACFT LISTED TO THE RIGHT. THE PLT COMPENSATED WITH AILERON CONTROL. HOWEVER, AS THE ACFT SLOWED DOWN DURING THE ROLL-OUT, THE RIGHT WING DROPPED TO THE SURFACE & THE ACFT VEERED OFF THE RIGHT SIDE OF THE RWY. IT CAME TO REST WITH THE RIGHT GEAR PARTIALLY COLLAPSED & DAMAGE TO THE RIGHT WING TIP, RIGHT MAIN GEAR STRUT DOOR, SPEED BRAKE & OTHER 2 GEAR. APRX 12 MI SOUTH SOUTHEAST AT WILMINGTON, DE, THE WIND WAS FROM 200 DEG AT 16 GUSTING 26 KTS.