MP4 will be the future, (Christian did you ever read my final post in the --r3mix thread here?
Anywayz the way im going to try and get it to work, is to scan the AAC file first and find the biggest block (in AAC this varies a hell of a lot) & set the blockalign to that in a copy of the VBR Mux code in Nandub & start from there...
-Nic