How do I use a bindings file when working with a wsdl?

I have a wsdl file that I can generate objects from just fine with the plugin when I don't try to provide a bindings file. However, because the schema is inside it I'm unable to point to the node for manipulation.
For example:
``` xml

```
throws a SAXParseException2, `XPath evaluation of "//xsd:schema/xsd:element" results in empty target node`
Can you give an example of how you would attach a bindings file to a `wsdl`? While, in my example I'm trying to alter the generated class name, this also relates to the page on [package binding](https://github.com/highsource/maven-jaxb2-plugin/wiki/Configure-Target-Packages-in-Binding-Files).