ACR LGT OVERSHOT ALT ON DESCENT.

Narrative

WE WERE CLRED TO DESCEND FROM FL260 TO 11000' (BE AT 11000' 30 NM NE CORPUS VOR). THE CLRNC WAS GIVEN APPROX 55 NM NE OF THE STATION WHICH REQUIRED A VERY HIGH DESCENT RATE TO REACH THE XING ALT (5-6000/ MIN) ADDING TO THE PROBLEM WAS AN UNUSUAL CONFIGN OF THE ACFT AUTOPLT. I HAVE NEVER SEEN THE TYPE BEFORE AND WAS UNFAMILIAR WITH THE OPERATION. THE RATE OF DESCENT WAS NOT ENOUGH AND THEN BECAME TOO MUCH (FOR A RATE OF LEVEL OFF PROVIDING PAX COMFORT). I DISCONNECTED THE AUTOPLT AT 12000 AND PULLED ABOUT 2 1/2 G PULLUP TO STOP THE DESCENT. I OVERSHOT THE ALT BY 500' (DOWN TO 10500') AND RETURNED TO 11000. THIS WAS ACCOMPLISHED AT 31 NM NE OF THE FIX (1 MILE PRIOR TO THE RESTRICTION). CONCLUSION: HAD I HAD MORE TIME TO MAKE THE DESCENT I WOULD NOT HAVE OVERSHOT. HAD THE EQUIPMENT IN THE ACFT BEEN STANDARD FOR OUR AIRLINE; I WOULD HAVE NOT OVERSHOT. SUPPLEMENTAL INFORMATION FROM ACN #88741: WE WERE CLRED TO CROSS 30 MI NW OF CRP AT 11000'. F/O FLYING GOT BEHIND ON DESCENT PROFILE AND OVERSHOT LEVEL OFF ALT; BY 500'. SUPPLEMENTAL INFORMATION FROM ACN #88893: THE COPLT TRIED TO OVERCOME THE EXCESSIVE RATE OF DESCENT USING THE AUTOPLT WHICH WASN'T RESPONSIVE ENOUGH.