CodeIgniter Web Services Client

[eluser]afirdaus[/eluser]
Im newbie in CI, i want to retrieve xml data from web services weblogic, the server locate to http://services.insw.go.id/web-services/...=getListGA and i wanto to get the XML Response from server, possible do this ??

i make funtion on controllers (resttest.php)

Code:

public function getRest()
{
    $this->rest->initialize(array('server' => 'http://services.insw.go.id'));

    $lartas = $this->rest->get('web-services/nsw',array('operation.invoke' => 'getListGA'),'xml');
    die(var_dump($lartas));
}

sometimes i got error like "array(0) { }" and if i refreshed, i got all HTML view same like i browsed http://services.insw.go.id/web-services/...=getListGA

am i wrong or missing some step ? or any suggestion to change this code ??

NB: I used https://github.com/philsturgeon/codeigniter-restclient

Thanks In Advance