I am sorry about the misunderstanding, however, please note that this is the non-MVC Kendo UI forum and you have not indicated that you are using the MVC helpers. Hence my reply was targeted at the pure client-side Menu widget.
You can set Encoded(false)
for the item and inject the desired HTML markup with Text()
the Telerik team
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI