Ok, sorry for the late reply
Well this has worked for me so far with Kodak film only (Tri-X and Portra). I actually wasted a whole roll of film just to test it to find out exactly how to line it up, this works for the 530/16 i'm not sure about later models, if the red window is in exactly the same place it should work
Anyway this is what I have come up with -
1. Load the film as usual - make sure the film locking device is disengaged when you do so (the picture counter needs to be past 11) and leave the red window open.
2. Wind the film on slowly until an arrow appears in the red window and stop when it is centered, you can shut the red window now
3. Wind the film winding knob on exactly two full revolutions (my Ikonta has a black dot on the knob making this easier)
4. Hold down the picture counter disc and turn it until it reaches "1"
And that is it for the first section, in reality it is exactly the same as loading normally except the film should not be wound on so far as "1" in the red window - in doing so you are just wasting film, the two turns from the arrow method I worked out as being perfect for Kodak film by testing it with the back opened (thereby wasting that film)
5. Take all eleven exposures as normal and then wind the film winding knob on once more until it reaches where a "12" should be on the picture counter disc (my camera also has a black dot here indicating so)
6. The shutter wont release here as the film locking device has become disengaged so hold down the picture counter disc until it goes round to "1" again and you feel a resistance (film locking device engaged)
7. Take the 12th exposure!
8. Wind the film winding knob on until the picture disc reaches "2"
9. Set the shutter tension lever as if you are going to take another exposure, hold down the shutter release knob and at the same time press down and rotate the picture counter disc until the counter passes "11" (this is so the film locking device once again becomes disengaged)
10. Turn the film winding knob on until the film has been fully transferred to the other sprocket
11. Take film out and have developed!
This all sounds quite complicated as I read it back but it really isn't, just practise and it's worth it to get that extra exposure!
Here is an image that should explain the red window process -
Once that arrow is in the window - wind on twice and the window will now have no indicator to show where it is yet this image shows you where it actually is in relation to the "1"
(It needs to be inbetween the 6x9 "1" and the 6x6 "1" - if you match it up to the 6x6 "1" as I thought it best to do first until I tried it with the back off then this is too early and the film isn't fully covering the lens opening)
Hope this helps someone
Cheers!
Richard