You don't need any special software to change the Icon number.
You can simply use your PC. Go to the folder where you place you styles and RENAME the style's ending "S" number to what you want it to be. (or it's "T" number)
For example here is style's Full Name:
Folsom Prison.
S651.sty
Just change the S651 to what you want the icon number you wish it to be.
Folsom Prison.
S653.sty
Easy to do.
Regards
Drake