Hi,
Just some pointers, as not much can be derived from your post.
Have a look at your proxy structure's namespaces against the WSDL or the Service definitions (dependant on outside-in or inside-out development).
1. Make sure the subnode namespaces are properly prefixed with the namespace URI. For subnodes that does not carry a namespace tag, your might need to explicitly mention as undefined (form=undefined). This is not good xml practice but hey.. 
.
2. Check your proxy definition, and may need to regenerate.
Kind regards,
Kapila