Using the DBMS_XMLGEN.GETXML package in R12 verse 11i.

Hello All,
I have noticed that for some Oracle Reports in R12 that the first line of the XML file has the following:

<?xml version="1.0" encoding="UTF-8" ?>

The following query only has this as the first line in the XML file:
<?xml version="1.0"?>
SELECT DBMS_XMLGEN.GETXML ('select * from mtl_system_items_b') XML from dual; /

My question is how can I get it to put the encoding portion in there?

Thanks,
Chris