Ah, so that could work if we get it to seem like it happened that way. Excellent.
We could say that one of our men were sent to find out what the freighters were carrying, since we had suspicions. Nothing illegal about an Imperial inquiry, eh? Our motives for the inquiry, though, might be called into question. I'm not sure what would be most feasible.
We find out, we debate as to whether or not to raise the blockade over it, Lord Vader has the final say and raises the blockade against these ships.
I'm not sure how we could fake that. Can't we simply publish the weapons manifest that I took and say it's the one we retrieved form the remains of the freighters? Then ask why they tried to run from a star destroyer?
I'd think running from the Imperial Navy is suspicious in itself. On a side note, would it be possible for us to identify the ship that followed them up into orbit?
Which is a good point, actually. Why would they try and run if they've nothing to hide?
A couple other things I thought of were that the altered manifest has to be an edited version of the real one, so if there's any sort of timestamps on it that could help, as well as investigating the altered one for any inconsistencies. Not to mention that if there's the risk of holes being poked in our stuff if we tried to forge it, it should be possible to find holes and mistakes in the faked manifest that would show it to be edited.
And for that matter, would it be possible to say that when inspecting the computer record, we found two copies of the manifest - the original that Lyle found, and the faked one?