Accessing SOAP service

I am trying to post a transaction to a SOAP service using the

require 'soap/wsdlDriver'

class CitymainServiceV2

  def post_policy(*args)
    soap = wsdl.create_rpc_driver
    soap.wiredump_file_base = "soap-log.txt"
    soap.wiredump_dev = STDERR
    response = soap.CreateCustomer(*args)

    def wsdl'

The api documentation on soap/wsdl is not at all useful and I am
really struggling to find a relevant tutorial. I was hoping to be
able to use this library without having to go into a lot of research.
The webservice is on .net and I would like to know how to accomplish
the following:

- I can connect to CreateCustomer but how do I specify
- for the post data, currently passed into the class a *args, what am
I meant to be sending in, a fully-constructed xml string using
builder? Perhaps a hash with appropriate symbol keys?
- is there a better way?