These revisions usually create new replaceable parts and thus sometimes is confusing to what parts go to what models. In this case we are going to look at the Sidi Crossfire SR and it's replaceable sole.
The original replaceable sole on the Sidi Crossfire SR used regular 10mm screws. In 2006 Sidi created a new version of the sole that solved two issues they were coming across. One being the build up and water and dirt within the long threaded screws caused more stress to the customer when trying to replace them. The other being their other soles (the hard and soft compound Super Moto soles) didn't fit as snug as they would like around the outside lip of the boot. Below you can see a comparision of the older Sidi Crossfire SR boot soles and the current 1/4" screw soles that come standard on the Crossfire SR. The area in red show the change in molding giving the sole a more snug fit (especially for the Super Moto soles...)
So you have a pair of the 2006 and before Sidi Crossfire SR boots and would like to replace the sole? What do you need?
1.) If your screws are still in usable condition...awesome. If not, you can purchase them at a hardware store. 10mm is what you are looking for.
2.) A new sole and a dremol tool, orbital sander, or something that you can use to grind down the area on the outside of the new sole to fit into the older molding. A bastard cut file may work as well, but you will most likely want to use something mechanized.
The image below displays the older version on top of the newer version giving you an idea of the area of sole that will need to be shaved down to fit.