If you want to break the fabric in a little try this.

It worked on my Cammies in the Marine Corps. A couple Jar Heads can probably tell you the same. If you starch the hell out of your Kilt, not cheesy spray starch but I mean Sta-Flo liquid starch to the kilt Soak it in the starch. You need to work it in real well, I used to use the bath tub but for a kilt maybe the sink. Once the kilt is soaked in Sta-Flo. Drip dry it over the sink (careful not to waste any of the liquid). Once it will not drip to much take it outside and hang dry it. Once the kilt is dry it should be stiff enough to stand on it's on. Now
Simulate a day’s wear crumple it up and wrinkle it all up over and over. You can toss it in the dryer on medium heat for a while too, get it all wrinkled up. Now wash the starch out.

The more you repeat this, the softer the cloth will get. The starch breaks down the material and helps soften it up. For a pair of old woodland cammies it takes a month of normal wear and starch to loosen them up. For a kilt it may take a little longer but you will be simulating the wear so it may go faster. Good luck, (I have tried this with a couple of pairs of Dickies pants that I wore for work a while back and worked like a champ.)

If you can get your hands on some rice starch, that stuff is amazing! the Lady that worked in my Barracks in Okinawa used it on my cammies and they were stiff as plywood but it lowered the life of them from maybe 2 years to 10 months.[/img]