LTT CPR CREW HAD SMOKE AND BURNING ELECTRICAL ODOR IN ZMA OCEANIC.

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CRUISING ALONG AFTER NORMAL DEP FROM FREEPORT; BAHAMAS. AT ABOUT FL220 IN CRUISE FLT; WE STARTED SMELLING AN ELECTRICAL SMOKE SMELL GETTING WORSE FAST. I TOLD THE COPLT TO TELL ZMA WE NEEDED A DSCNT ASAP DUE TO SMOKE IN THE CABIN. WE GOT A DSCNT TO 10000 FT WITH A TURN TO 360 DEGS AS WE TRIED TO ISOLATE THE PROB. THE SMELL KEPT GETTING WORSE. WE DID OUR MEMORY ITEMS ON THE CHKLIST WHILE REMOVING PWR FROM THE AIRPLANE BY SWITCHING THE GENERATORS TO 'OFF.' THE SMELL STILL SEEMED TO GET WORSE. WE WERE TOLD; IN THE MEANTIME TO MAINTAIN 11000 FT; BUT WE WERE ALREADY AT 10000 FT AND VERY BUSY. WHILE AT 10000 FT; WE ISOLATED THE SOURCE OF THE PROB; SWITCHED THE WINDSHIELD HEAT OFF; PULLED THE 60 AMP CIRCUIT BREAKER TO THE AFFECTED WINDSHIELD (COPLT WINDSHIELD BEHIND GLARE SHIELD; ARCED AT WIRING AND WAS SMOKING BADLY). THIS ISOLATED THE PROB. I HAD THE RADIOS AT THIS POINT AND WE WERE ABLE TO GET A CLB BACK UP TO ABOUT 16000 FT TO CONTINUE THE FLT TO FLL TO GET MAINT TO CHK THE PROB OUT. ONCE THE AIRPLANE WAS CHKED OVER; WE GOT A FERRY PERMIT BY THE FLL FSDO TO FLY THE AIRPLANE BACK TO CHARLESTON; SC. WE HAD NO FURTHER PROBS AFTER THE WINDSHIELD HEAT WAS TURNED OFF ON THE COPLT'S SIDE. BY THE WAY; WE OFFERED ON OUR XMISSION TO ZMA; AFTER WE TOLD HIM WE WERE ALREADY AT 10000 FT; THAT WE COULD CLB BACK UP IF NEEDED. HOWEVER; WE WERE ALREADY AT 10000 FT DUE TO MAX PERFORMANCE DSCNT. ALSO CONTRIBUTING TO XPONDER AND XMISSION DISCREPANCIES WERE THE AIRPLANE'S PWR BEING TURNED OFF AND BACK ON AGAIN.