The most common way to do it is to shorten the strut a little and also use a spacer in the bottom of the strut. The HTS102's are somewhere around ~60mm shorter than OEM. How much you shorten the strut depends how low you want the car to be. Then the remaining space you fill out with a spacer. I recently fitted HTS102's to my struts, I shortened the strut tube by 40mm and then spaced the bottom of the strut by about 20mm.
I used a coilover sleeve kit which allows you to adjust the height of the front suspension. Are you using a coilover sleeve kit as well? If not this may not be suitable as you will need consider the spring height of the non adjustable set-up?