How to change peer_id

[cms42]

I'm trying to make BitComet work with private trackers. As we all know, they have a very critical restriction of torrent clients. In most cases, it's done like this:

array (
                'id' => 21,
                'family' => 'Transmission3.x',
                'start_name' => 'Transmission 3.0',
            'peer_id_pattern' => '/^-TR3([0-9])([0-9])([0-9])-/',
                'peer_id_match_num' => 3,
                'peer_id_matchtype' => 'dec',
                'peer_id_start' => '-TR3000-',
            'agent_pattern' => '/^Transmission\\/3\\.([0-9])([0-9])/',
                'agent_match_num' => 3,
                'agent_matchtype' => 'dec',
                'agent_start' => 'Transmission/3.00',
                'exception' => 'no',
                'allowhttps' => 'yes',
                'comment' => '',
                'hits' => 0,
            )

So what we need to do is to change the user agent and the peer id of BitComet. I know how to change the UA; however, am I able to change the peer_id?