From a g**gle, it appears that with a basic stepper motor it isn't possible. You need some kind of extra physical end-stop (end of carriage on a plotter, or 3d printer?) . Suggestion is to count the steps and return to that point. Not perfect, but seems that's it.
This might help:
http://www.explainthatstuff.com/how-ste ... -work.html
p.s. I wanted to set up a stepper based single hand clock, but setting the time is the problem!! Project on hold!