[Koha] Koha item call numbers

I seem to recall in the past that there was a nice little walk through provided by someone on how to get koha working with a multi part call number (using the k, h, and i) subfields, but, I can not seem to find that information anywhere in the archives or linked from the howto's. Anyone able to point me in the correct direction or give some pointers on how to keep the three separate subfields and also have koha display them as a single call number? Tim