How do you enable xsi:type generation when serializing a class?

[Bishop]

I have a location-list class which serializes to:

<?xml version="1.0" encoding="utf-16"?>
<location-list xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http ://www.w3.org/2001/XMLSchema">
...
</location-list>

but I want to include the xsi:type in the location-list node:

<?xml version="1.0" encoding="utf-16"?>
<location-list xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http ://www.w3.org/2001/XMLSchema" xsi:type="locat ion-list">

Would I do this at the class defintion?

<System.Seriali zableAttribute( ), _
System.Xml.Seri alization.XmlTy peAttribute("lo cation-list",
[Namespace]:="my-service-URI")> _
Partial Public Class LocationList
....
End Class

or at the serializer?

Dim loclist As New LocationList
Dim xmls As New System.Xml.Seri alization.XmlSe rializer(loclis t.GetType)

Thanks