@PimUigi+magz: I said this a long time ago, ACData.bin is most likely the file that has the Announcer samples, if you know of any sort of binary byte interleave editor that can mess with that format (read: unzip and replace files), then it's possible, otherwise, so far, no means.
@UltimaOriginal: Getting stuff to be the exact size doesn't necessarily mean timestamp length, it could also be the kind of compression you're using for the WAVE file. Also, this isn't always a perfect process and in my case it often took me several test runs before I actually got it to work, so don't be afraid to make the ISO a couple times. Just don't burn any CDs until you know it's gonna work for sure.
@Teyah: Don't be a dick. :E I've seen ways of editing CSOs on PSPMod forums. CSOs aren't different from ISOs, they just use a different compression method. I could probably edit BlazBlue's tracklisting if I knew the compression, they did it with Dissidia already.