A319 CREW EXECUTED A GPWS EMER ESCAPE MANEUVER WITH CLB UNTIL THE GPWS TERRAIN WARNING STOPPED. ACFT WAS AT THE MINIMUM VECTORING ALT AT THE TIME OF OCCURRENCE; IN MHT CLASS D.

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ON ARR INTO MHT IN EXCELLENT VISUAL CONDITIONS; WE WERE CLRED TO 1800 FT MSL BY MHT APCH; AND THEN CLRED FOR A VISUAL APCH TO RWY 17. THERE ARE HILLS CLRLY VISIBLE TO THE NW OF MHT; AND OUR FLT PATH WAS CLR OF TERRAIN AS WE APCHED THE HILLS. OUR RATE OF DSCNT WAS APPROX 1300 FPM AS WE APCHED LEVEL OFF AT 1800 FT; AND AS WE PASSED THE HILLS; WE RECEIVED A SINGLE 'TERRAIN; TERRAIN -- PULL UP!' GPWS WARNING. WE RESPONDED BY CLBING BACK UP TO APPROX 2300 FT MSL UNTIL CLR OF THE HILLS AND THEN RESUMED OUR APCH FOR A NORMAL LNDG ON RWY 17. IT IS MY OPINION THAT THIS WAS CAUSED BY THE GPWS READING OUR MOMENTARY RATE AND ANGLE OF DSCNT; AND IT WAS VALID AS A WARNING; AND OUR RESPONSE WAS CORRECT TO CLB UNTIL COMPLETELY CLR OF TERRAIN. NOT TFC CONFLICTS; NO OTHER SAFETY ISSUES; APCH WAS NORMAL AND LNDG WAS NORMAL. LATER REVIEW OF THE APCH CHART TO MHT REVEALED THE PRESENCE OF 3 NOTED HILLS TO THE WNW OF MHT; ELEVATIONS INDICATED ON THE CHART WERE 2300 FT MSL AND 2066 FT MSL RESPECTIVELY. ONE OF THESE POINTS WAS THE PROBABLE CAUSE FOR THE WARNING; BECAUSE OF THE HDG TO JOIN FINAL THAT APCH CTL HAD ASSIGNED.