CurrentLevelsDisplayed attribute added to HTML of an asp:SiteMapPath

When I use an asp:Sitemappath control the HTML it generates automatically adds a "CurrentLevelsDisplayed" attribute to the span node it generates around the sitemap. This obviously fails in W3C.

How can I get rid of this a开发者_如何转开发ttribute in the HTML? I know it can be done as I've seen projects with an sitemappath control that do not generate it. Unfortunatly just coping most of the structure of that control doesn't seem to work.

This is my control at the moment:

            <asp:SiteMapPath ParentLevelsDisplayed="7" 
                                     ID="smpWebSite" 
                                     runat="server" 
                                     PathSeparator=" &gt;&gt; " 
                                     PathSeparatorStyle-CssClass="PathSeparator"  
                                     SiteMapProvider="Public"
                                     OnItemCreated="SiteMapPath_ItemCreated" 
                    >
                    <PathSeparatorStyle CssClass="PathSeparator"></PathSeparatorStyle>
                    </asp:SiteMapPath>