Savon: Use complex SOAP types as arguments

If a SOAP API expects you to call a remote method with arguments of complex types, Savon Show archive.org snapshot lets you manually set the xsi:type attribute like this:

client.call(:rpc_method,
  message: {
    :some_object => {
      :name => 'foo',
      :other => 'bar',
      '@xsi:type' => 'somenamespace:SomeObject'
    }
  }
)

This is roughly equivalent to this in Javaland, where you have magic generated stub code:

SomeObject so = new SomeObject();
so.setName('foo');
so.setOther('bar');
client.rpcMethod(so);