For an example, and while this is usually the method of sorting out an issue (sorry xbeerd) with a photo, in this case you simply cannot state that your alternator has two wires or three, the alternator's wiring diagram is what is key to this issue.
if your alternator has lost it's sticker, which can happen, you need to find someone with the same alternator or a wiring diagram for that model of alternator to work it out. If the letters don't line up, as in there are different letters used then they will have to be found out before you can match it up with the diagram below. I would like to note again that the below diagram isn't the answer to all alternator wiring conversions, it is for the Gen1 and I believe Gen2 alternators...
I hope this helps out, it all comes down to the wiring/plug diagrams!
its ok, i'll get over it, but anyways... are you referring to the plug diagram that is on the right side of my pic? labelling S and L in the plug?