In all cases,
DynamicMenuItemStyle
is not an HTML element, hence, it cannot have the CSS class.
You can run your application and look how the menu code looks from the browser, to see how it works in terms of HTML. To do so, just load your page in the browser and look at the HTML code through "View Page Source" (or something like that, which depends on the browser). Always a good exercise. :-)
To see how menu is actually styled, please pay attention for the code sample in the MSDN page on
DynamicMenuStyle
:
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.menu.dynamicmenustyle.aspx[
^].
—SA