Web Service with no value returned

Rails
1

In the Agile Web Devopment with Rails book, it says (p 427) that
omitting the :returns option from a web service api, the method will
“return nothing to the caller”.

However, I have written a test and invoked it from the browser. It says
“return value nil” but XML response:

<?xml version="1.0" encoding="UTF-8" ?>

<env:Envelope xmlns:xsd=“http://www.w3.org/2001/XMLSchema”
xmlns:env=“http://schemas.xmlsoap.org/soap/envelope/”
xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”>
env:Body
<n1:LoginResponse xmlns:n1=“urn:ActionWebService”
env:encodingStyle=“http://schemas.xmlsoap.org/soap/encoding/”>
</n1:LoginResponse>
</env:Body>
</env:Envelope>

Is it possible to have a web service which really returns nothing? I
just want to log calls to the web service and do not need anything at
all passed back to the client.

Thanks,

Julian