Oolite Bulletins

I've been playing the Iron Raven mission for a while and it seems to have come to a dead end. The current message in F5 is: "Iron Raven: Meet Major Cherkasova in orbit around Maenes.". However, I have already met him, followed his instructions, shot down all the SPF landing ships (or whatever they were) and got the impression that task was complete. So I'm expecting something else to happen now; but when I return to Meanes there's no Major around, and things just appear as normal with all the cannons around the space station. What ought to be happening next? It just seems like the script has ended in a dead-end.

After you destroy the landing craft you should be told to attack the SDF's flagship, the Imperator. Do you know if you've done this - or is it even appearing in on orbit in Maenes?

It hasn't appeared and there was no mention of it. My oolite-save file has these lines, which are probably the relevant ones: Could I be lacking another OXP that's required for Imperator to appear?

No you shouldn't require another OXP for that ship to appear; what's more it should appear right next to the transporters you have to shoot down. Unfortunately it's not marked with a beacon but you should be able to spot it from a distance.
To restart this section, change the mission_IR_status in the save file to "IR_LOA_5", re-launch from Maenes (or hyperspace back in) and things should reset.
However it sounds like you've done most of the hard work anyway and so if you just want to move to the next stage, set the same status to "IR_LOA_6" and dock again at Maenes.

The change back to IR_LOA_5 fixed it. This time the Imperator was there along with all the landing craft. So I appear to back on track now. Thanks for the help!