Well if you have everything hooked up correctly and it's sending a negative pulse and the alarm is still not deactivating then the negative pulse apparently isn't what it needs. You might try disconnecting the negative pulse lead, have a positve charge ready and try the remote start again. If the positive doesn't do it either then try back tracking and make sure you have it wired and grounded right and make sure you have the correct voltage going to the alarm.
__________________
1989 240SX Fastback. . . . . . . . . . . . . . . . . . . . . . . . . . . 1995 300ZX Twin Turbo
Warning: Objects in mirror aren't as fast as they thought they were.