Using the entity framework with a MySQL DB and the model designer doesn't pickup stored proc parameters

Question

I've got the latest Mysql connector that allows you to use the Visual Studio Entity Framework designer. It's been working great, but I just added a stored proc.

The Server Explorer loaded it up fine with the parameters specified, but then I added it to the Entity Model & the code it generates doesn't have any input parameters.

Here's the stored procedure

CREATE PROCEDURE `GetViewableMenuNodes`(IN siteId INT, IN parentId INT, IN userName varchar(255))
BEGIN
    select m.*
    from menunode m 
    where m.siteid = siteId
    and m.showinmenu = 1
    and m.parentid = parentId
    and m.viewername = userName;
END

and this is the code generated by the model

public global::System.Data.Objects.ObjectResult<MenuNode> GetViewableMenuNodes()
{
    return base.ExecuteFunction<MenuNode>("GetViewableMenuNodes");
}