Bird 2.0 OSPF to OSPF redistribution cost

I am trying to set up bird for routing networks between my sites witch are connected with 2 L2 links. Right now all my OSPF_INTRA are redistributed to others routers with automatic cost calculation. I would like to specify extra cost for some network in order to "force" traffic to pass on the other link. (eg. Real-Time traffic on the first link and Bandwitdh consuming traffic on the other by tweaking cost). Regards, Nicolas