gstreamer passing cookie http header via URI

Hi All,
We are trying to create a vod plugin for enigma2 but have an issue,

our play code is below, which is working w/o any problem for many vod streams,
but some links requires special http header like custom user-agent and also cookie.

self.reference = eServiceReference(4097, 0, self.vod_url)
self.reference.setName(self.title)
self.session.nav.playService(self.reference)

http headers are below for the player;

Hypertext Transfer Protocol
	GET /hv/42520740.mp4?sign=9445ae0ee23498b992450b38ac3ee4ca8133ede7&slave[]=s%3Ahttp%3A%2F%2F127.0.0.1%3A5010%2F42520740-hv.mp4&p=0&expire_at=1372967538|video_key=88265 HTTP/1.1
 
	Request Version: HTTP/1.1
	Host: cdn9.video.mail.ru
	Connection: close
	icy-metadata: 1
	transferMode.dlna.org: Streaming
	User-Agent: Dream Multimedia Dreambox Enigma2 Mediaplayer
   
	[Full request URI: http://cdn9.video.mail.ru/hv/42520740.mp4?sign=9445ae0ee23498b992450b38ac3ee4ca8133ede7&slave[]
=s%3Ahttp%3A%2F%2F127.0.0.1%3A5010%2F42520740-hv.mp4&p=0&expire_at=1372967538 cookies=video_key=88265]
	[HTTP request 1/1]

But I want to add a cookie header to the http request which will be send via URl (video_key=88265).

Is there any way of altering http headers for the player?

Many thanks in advance for any help.