Controling XML Serialization

Hi to all,

XML Example into msdn documentation,

publicclass Group{
    [XmlArrayItem(Type = typeof(Employee)),
    XmlArrayItem(Type = typeof(Manager))]public Employee[] Employees;
}publicclass Employee{publicstring Name;
}publicclass Manager:Employee{publicint Level;
}  
This serialize into XML :
<Group><Employees><Employee><Name>Haley</Name></Employee><Employee xsi:type = "Manager"><Name>Ann</Name><Level>3</Level><Employee></Employees ></Group> 
How add attribute serialization for serialize in this XML ?
<Group><Employees><Employee><Name>Haley</Name></Employee><Employee>
<Manager><Name>Ann</Name><Level>3</Level>
</Manager><Employee></Employees ></Group> 
ok is need to add XMLInclude of type manger but for requeriments of mi client i need to "convert manager type in 
data element"
Thanks , to all
Jordi     

Jordi Burgas