How to remove Menu item attributes for my sitemap???

I am using nice menus in my site and I put a horizontal line to divide the childs in my vertical menu in my menu item attributes like this
border-bottom: #000 1px solid; padding-bottom: 10px; margin-bottom: 10px;
my problem is that now that I am creating my sitemap using menu tree or sitemap, my sitemap is being displayed with that horizontal line too!! could anyone tell me how to do this in a different way or how to call these menus without that style for my sitemap???? thanks anyway!