Alter submitted by text and retain RDF tags I am looking to change the submitted by text from:

&lt;span rel="sioc:has_creator" datatype="xsd:dateTime" content="2011-03-20T22:54:29+13:00" property="dc:date dc:created"&gt;Submitted by &lt;a property="foaf:name" typeof="sioc:UserAccount" about="/users/author" xml:lang="" class="username" title="View user profile." href="/users/author"&gt;author&lt;/a&gt; on Sun, 20/03/2011 - 22:54&lt;/span&gt;


to:

&lt;span datatype="xsd:dateTime" content="2011-03-20T22:54:29+13:00" property="dc:date dc:created"&gt;Date posted: 20 March 2011&lt;/span&gt;


I know how to alter the text in node.tpl.php but I do not know the function that will return the date formatted with the RDF tags around it. Does anyone have experience in this area?
The function that returns the content of that tag is date_iso8601().
To understand how those tags are output, you should look at rdf_preprocess_node() and rdf_process().