check out this site there you will find an article about sewing the straps on your kilt.
http://users.tinyonline.co.uk/chegc/kiltsite/kilt.htm

thats a link to the main page

http://users.tinyonline.co.uk/chegc/kiltsite/page2.htm

there is the link to the page that contains what you require.

hope this helps you out.