Savon: Adding an encoding to the body tag-Collection of common programming errors

How can I add an encoding attribute to the body tag using Savon?

Some background: I am trying to use savon to connect to a SOAP resource. I can get the WSDL file and browse through the methods.

@client = Savon::Client.new("http://some.domain.com/v2messaging/service?WSDL")

when I try to use the login method

response = @client.request :service, :login do
  soap.body = { 
    "String_1" => "username",
    "String_2" => "password"
  }
end

I get this error:

Failure/Error: response = @client.request :service, :login do Savon::SOAP::Fault: (env:Client) caught exception while handling request: unexpected encoding style: expected=http://schemas.xmlsoap.org/soap/encoding/, actual

The difference in the body tag. Here is the expected xml (found through SOAPUI application):

   
   
      
        username
        password
      
   

Savon sends:

    
        
            username
            password
        
    

There are a few difference between these, but the error returned has to do with the env:encodingStyle attribute on the env:login tag. How can add this attribute?