I found some code for setting 'names' in the soap call, and tried:

    import SOAP::Data 'name' || print "\n!Couldn't import!\n";
    eval {
        $service = SOAP::Lite
            ->name('username' => 'user')
            ->name('password' => 'pass')
                    ->service('http://server/file.asmx?WSDL');
    };  #|| ($_); # $@ will have the error message, perldoc -f eval
[download]

But I get an error:
Can't locate class method "name" via package "SOAP::Lite" at script.pl line 98

This closer?