All you would have to do is put Jabba's palace in the background of the first Sail Barge shot, so as they are approaching us you see the Slave 1 lifting off in the far back left area and jet away. That way you could keep Boba in the Jabba scenes earlier (so he can get his screen time) yet takes off for another mission, whether its the Death Star plans or not

- in fact, what if Jabba had the plans [from the rebel spies he had killed] and gave it to Boba? That Boba wasn't so much working for the Emperor as the rebels just offered a price too good to pass up? Someone could edit a scene to either show Boba and Jabba a little out of focus in the background with Jabba handing Boba a box or disc (with the foreground characters talking) or right before the Sail Barge shot showing Boba come from behind Jabba and have Jabba hand him the data.

Another idea is when his rocket pack is hit by Han, rather than have him bounce off the side of the Sail Barge, just have him go inside on the side windows or crash through the side wall. When Luke is on the main Sail Barge, take some shots of Boba so now he is on the top deck; when Luke and Leia start causing havoc and the destruction begins, take a line out of the Holiday special (right before he takes off and escapes) and have him shoot straight up into the sky and get away just like the Holiday special cartoon. You could possibly modify some shots from THE ROCKETEER or something.