You can find good examples Here for how to use Soap::Lite.

I think the big difference between your C# code and the Perl implementation is that C# is auto encapsulating the data into XML for you. Soap::Lite is middle ware used to send the data to somewhere else. You will probably have to write some code to encapsulate the data yourself.

You should also consider taking a look at XML::Simple or XML::Twig on how to generate a XML document. Or you can use a template if the document is simple enough.