<das:attribute> tag describes an xml attribute in the resulting XML.
<das:attribute id="attr1" name="id" value="fld1" namespace-prefix="ns" namespace-uri="http://mycorporation.com"/>
Attributes:
id - unique identifier of this resource in the current processing job.
name - the name of the element in the resulting XML.
namespace-prefix - the prefix of the namespace of the resulting XML tag.
namespace-uri - the URI of the namespace of the resulting XML tag.
value - attribute value.
Note! The value field must be a reference to a <das:function> result or to a <das:field> element.