WebPlus X6: Full width slider in WPx6 with html code

Hi,
can anybody help me?
I have buy a third full width slider. Now my problem:
When i put the code in WPx6 as HTML the slider shows on browsers only the size of my side, no full width. When i make the HTML window at the size of the slider code and make it in the middle, the slider is not correct on the browser. Any idea??
Thanks