you need to measure the resistance between the connections on the new motor.

http://www.talkingelectronics.com/pr...pperMotor.html

Just down that page a short way is an explanation of the difference between 4, 6 and 8 wire steppers. You can see that centre to outside will be half the resistance of outside to outside. Using that you can draw the wiring of the pins for your new motor. Repeat for the old motor and see if they are the same.