FOR XML Support for the timestamp Data Type

In the FOR XML transformation, timestamp type values are treated as varbinary(8) data and will always be base 64 encoded. The XSD or XDR schema, if requested, reflects this type.

drop table t
go
create table t
(c1 int,
 c2 timestamp)
go

insert t values(1, null)
go
select * from t
for xml auto, xmldata
go

This is the result:

  <Schema name="Schema1" 
          xmlns="urn:schemas-microsoft-com:xml-data" 
          xmlns:dt="urn:schemas-microsoft-com:datatypes">
    <ElementType name="t" content="empty" model="closed">
      <AttributeType name="c1" dt:type="i4" />
      <AttributeType name="c2" dt:type="bin.base64" />
      <attribute type="c1" />
      <attribute type="c2" />
    </ElementType>
  </Schema>
  <t xmlns="x-schema:#Schema1" c1="1" c2="AAAAAAAAH04=" />