rFactor creates a panoramic, very wide picture that is "diplayed" on specified (in "miror" named material) mirror texture (typically that's mirror.bmp). Now, your job is to pick the right pieces from the whole texture and map them properly on the physical mirrors. If you pick center of the texture and map properly on cockpit mirror (center mirror), then you will get that right.
Apart from that, you can use a combination of Shift + "seat position" (which is up, down, fore and aft) to make mirror corrections in-game: angle up, down, left and right.
Beeing you, I would start with making sure that your in-game mirror settings are set to 0 for both axes. Then check material mapping becase if that's not the in-game settings, then it's definatelly something with texture mapping.
As for cockpitinfo mirror coordinates... i mentioned, that rFactor creates picture on the mirror texture. Imagine that you are that "rFactor". You are sitting with a camcorder in your hand looking towards back of a car and I'm telling you to put that camcorder to a position (XYZ) specified in cockpitinfo file. This is a very,very wide screen camcorder. What you see in it, is what you get on the mirror texture, which you map onto mirrors - objects.
These coordinates are XYZ coordinates telling ,where that POV (point of view) is for the "mirror camera guy" ;-)
Z coordinate is for fore/aft position and it's 0.0 is probably where is center of the car's model. 0.0 for X is at the line going through center of the car, front to back (+ to the left, - to the right).
0.0 for Y is probably at car's reference plane which is its bottom (the same plane, ride height is calculated and all other HDV stuff). + for the up and - is down.
Unfortunatelly, you can't do all mirrors right in rFactor 1. I hope ISI will consider providing better support for that, like I said them already a few times.
rF provides only one POV so typically you will place it inside your cockpit to have proper view and perspective for center mirror. Having it in that place, you will never see your sides of your car in exterior mirrors. That would be only possible if there will be available additional POVs for side mirrors (which will be placed independently on both sides of the car, where you have real side mirrors and at proper angles).
