I wonder if you are not taking into account the 'wrapper' or partition name. Here's what I get back from a curl request on a test box - I suspect this will help;
http://schemas.xmlsoap.org/soap/envelope/"
xmlns:A="
xmlns:s="
xmlns:y="
xmlns:iControl="urn:iControl"
E:encodingStyle=">
/Common/1.1.22.11 <<<<<<<<<<<<
The curl request looked like this;
curl -k -X POST --user "username:password" -H "Content-Type: text/xml;charset=UTF-8" -d @get_nodes.xml
And the get_nodes.xml file contained this;
http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd=" xmlns:soapenv=" xmlns:nodes="urn:iControl:LocalLB/NodeAddressV2" xmlns:soapenc="">
">http://schemas.xmlsoap.org/soap/encoding/">">