How to include array data in CURLOPT_POSTFIELDS?

I'm basically processing a HTML form with PHP and then sending it off elsewhere for storage and processing. However I'm having trouble sending array lists through curl. I need to do it in such a way that when it gets to the receiving server it's as if it has come straight from the input form.

I don't receive any errors when using the function if I serialize the arrays, however this makes them unreadable by the server, so they need to keep the post format as if they were coming from a HTML form.

I'm using Kohana but principles of Curl are still the same, here's my code:

            $path = "/some/process/path";
            $store = "http://www.website.com";

            $url = $store . $path;

            $screenshots = array();
            $screenshots[0] = 'image1.jpg';
            $screenshots[1] = 'image2.jpg';
            $screenshots[2] = 'image3.jpg';

            $videoLinks = array();
            $videoLinks[0] = 'video1.wmv';
            $videoLinks[1] = 'video2.wmv';

            $params = array(
                'id' => '12',
                'field1' => 'field1text',
                'field2' => 'field2text',
                'field3' => 'field3text',
                'screenshots' => $screenshots,
                'videoLinks' => $videoLinks,
            );

            $options = array(
                CURLOPT_HTTPHEADER => array("Accept: application/json"),
                CURLOPT_TIMEOUT => 30,
                CURLOPT_POST => TRUE,
                CURLOPT_POSTFIELDS => $params,
            );

            $data = Remote::get($url, $options);
            $json = json_decode($data);

Cheers.