Help with multiple returns in SOAP

Rails
1

Can anyone tell me how to push ActionWebService to create proper WSDL
for multiple returns?
My code looks like this:

class UserApi < ActionWebService::API::Base
api_method :getuserinfo,
:expects => [{:username => :string}, {:userpass => :string}],
:returns => [[{:firstname => :string}, {:lastname => :string}]]
end

The WSDL doesn’t include firstname and lastname names (only
StringArray):

And of course generates output:

    <return n2:arrayType="xsd:string[2]"
        xmlns:n2="http://schemas.xmlsoap.org/soap/encoding/"
        xsi:type="n2:Array">
      <item>Tomasz</item>
      <item>Tomczyk</item>
    </return>

How can get into returns without having returns names in external soap
client?
Having WSDL like the one above I can only iterate throu items, which I
think is not SOAP way.

Regards,
Tomasz Tomczyk