What year and model is your bike? It's helpful if you can state that in your sig. Do you have an owner's manual? Inside the manual it explains how to change the reading on your speedo from km/h to mph.
I don't know what year your bike is, but if you bought it new you can change it to miles. I'm guessing it isn't new, because you'd probably have an owner's manual, but that brings me to the next point.
Fill out your profile and show your bike and/or include your bike year and model in your sig line so that there's no such confusion down the line. Thanks, and after I find out how little help I was, perhaps we can zoom in on a solution.
After 50 pages of search results, and two KTMTalk threads, it seems that to enter your configuration mode, you need to press & hold the "0" until it goes into setup, then you should see the options along the bottom of the speedo. The threads mostly deal with wheel size, but if you're persistent with reading them, you'll find that all of the mention the kmh/mph configuration.
I am not sure about your year but if you have a problem getting to the menu to set wheel size pm me and I will give you "secret" if you promise to only help those of noble causes :lol:
Check out the link below to download the '04 Owners manual from Husaberg.se 2004 Owners Manual
Find the speedo information on pages 8 to 14.
On top of page 14 is a section called "kilometers or miles?"