So, when you relaunched Composer it didn't come back up to the "install your software" stage? If not, I guess that could be because the installer ungracefully force quit it, because normally its not an issue for Composer to start where you left off.
If so, you can try this instead-
Do your initial pre-installation capture, when Composer tells you to run your installer, quit Composer normally (don't let the installer do it for you), run your printer driver installer, relaunch Composer and it should come back up to the point where you can do your "after" capture.
That said, I would strongly advise not using Composer captures as they can miss stuff and not be the most reliable (queue a donmontalvo rant on Composer :D )
If this driver is in pkg or mpkg format, try using it that way. Of course, I assume if it quits apps when you run it it may do the same when pushed via policy or whatever, which could be a problem. (talk to the developer about that - shame on them)
If its not a standard installer, but is one of those custom "app" installers (man I hate those) then you might not have a choice but to do the Composer capture.
