I think the processes would be similar to approaching a potential television station. We can write to Netflix, either individually or as a group, asking for B5 to be added to the service. And follow that up with petitions, letter writing campaigns, etc. Again possibly tying it all in with the upcoming Sense8, to gain more attention.
Some intel gathering first might be good, too. Maybe we can find out exactly why the show was pulled. Did WB want more money than Netflix was willing to pay? Did they want the show exclusively on competing pay-per-episode sites? Were there other license issues involved? Royalties? Basically, what kind of hurdles are we facing here?
Who we can contact for that, I'm not sure. Netflix? WB? Someone with industry connections? I'd love to hear some ideas, too!