The Value element contains the value of an extended property.
A Value element can occur in both single and multivalued extended property instances. For single-valued instances, it exists as a direct child of the ExtendedProperty element. For multivalued instance, it exists as a direct child of the Values collection.
The schema that describes this element is located in the EWS virtual directory of the computer that is running MicrosoftExchange Server 2007 that has the Client Access server role installed.