Ok so I am not sure if its been covered but I recently tried to get creases out of my OG XII's and found some success. No before pics but I have an after. Here is all that I did to the shoe to make them look NDS.
1) Scrubbed shoes with wet washcloth
2) Took the laces out, threw them in with some laundry sprayed with stain lifter.
3) Armorall on the black sections (both leather and sole)
4) Took wet washcloth used earlier and layed it over the shoe
5) Turned an iron onto cotton steam setting and pressed the creases out *Note* this should be done with some sort of stuffing in the shoe to help give original shape
6) Repeated step 4 half a dozen times on each shoe. I ironed the lace areas where creases were, the tounge, and toebox.
7) Let shoe cool out, then went over it with Armorall leather protectant
And here is what they look like now...
Luckily the white part of the midsole is still pretty fresh so I didnt need to use any special cleaner. But to those with XII's looking to rid of creases in the leather, I highly suggest ironing. It works.