i am using webservice to get xml result by php

PHP Code:
            $xml=simplexml_load_string($xml); 
the problem is in the nodes , i got from webservice the nodes in this format ParentNode and other times in this format parentnode

how i can make the nodes only in lower case?????

without changing it's inner values to lower case...


e.g:


Before:

Code:
<ParentNode>
   <ChildItem TestAttribute="ValueCasing" >
	This text Will not Be Harmed!
   </ChildItem>
</ParentNode>
After:

Code:
<parentnode>
   <childitem testattribute="valuecasing" >
	This text Will not Be Harmed!
   </childitem>
</parentnode>