Change the output of the Html.menu() asp control .

Question

Im creating a asp mvc application and im using a sitemap to create my menu.

Is it possible to change the output of the Html.menu() asp control?

normal output:

<ul>
    <li><a href="#">Item 1</li>
    <li><a href="#">Item 2</li> 
</ul>

needed output:

<ul>
    <li><a href="#"><span>Item 1</span></li>
    <li><a href="#"><span>Item 2</span></li> 
</ul>

Or should i filter true the nodes of the sitemap to get the format i want??

TY in advance:)