Using word-wrap for an AspMenu SharePoint web control with long menu items

I have an AspMenu SharePoint web control with long menu items that do not respect the width of the table cell that I've set even though I have the property 'ItemWrap' set to 'True'. The biggest culprit is users wanting to use a series of  underscores to separate one group od links from another. To keep an extra long series of underscores from pushing the table cell wider, I'm using the stylesheet rule 'word-wrap' as shown below.

The ASPMenu control creates this hierarchy of tables. 

div#s4-leftpanel table tr td table
{
       table-layout:fixed;
}
div#s4-leftpanel table tr td table tr td
{
       word-wrap:break-word;
}