Camel route depending on header. Namespace breaks condition

I'm following the "Message Router" pattern explained in http://ift.tt/1Eyn7Dh However, I'm having problems with conditions on headers with namespaces.

The XML message I'm receiving is like this:

<SOAP-ENV:Envelope 
xmlns:SOAP-ENV="http://ift.tt/sVJIaE">
<SOAP-ENV:Header>
<DF xmlns="http://mycompany/smth">myElement</DF>
</SOAP-ENV:Header>
<SOAP-ENV:Body>
<ns2:processIncomingMessage xmlns:ns2="http://a.namespace.com/">
<arg0>something</arg0>
 </ns2:processIncomingMessage>
 </SOAP-ENV:Body></SOAP-ENV:Envelope>

And this is my route:

from("switchyard://CamelInterfaceService") 
                .log("Header: ${headers}") 
                .log("Received message for 'CamelInterfaceService' : ${body}") 
                .choice() 
                     .when(header("DF").isEqualTo("myElement")) 
                    .to("switchyard://OtherService") 
                    .log("SENT.........") 
                .end(); 

However, "OtherService" is not called.

If I change myElement to: myElement it works...but it is something I cannot really change...so, how can I modify my camel route to make it work?

Thank you!