Here's what I have on my blast. I have a similar set-up on the xb too.
I'm running fat bars, so I slid the controls as far in as I could. Then clamped the mirror to the end of the bar sticking out. I then used the leftover hardware from the mirrors, with a different bolt, to attach the end of the hand guard.
If you weren't running fat bars you could do the same thing but don't clamp the mirror to the bar and stretch the hand guard to the outside of the mirror with the different bolt. I did it this way too before I went to fat bars.
Matt