I am trying..lol
But my mp4 video files do not retain sound files during processing for export or "as save" as in Abode premiere pro cs5 software , my acceptable video formats. mpeg.(HD 900 mb) MPG(720p hd 123 mb) .MTL( Blueray HD video 332 mb ) .AVI MS uncompressed video 2,8 gigs, (DVDi low def 146 mb) Flash formats both fla and fva 680 x 400 max size 48 mb) H-65 HD mpeg for television and internet streaming media 335 mb)
I have adobe media encoder for transforming and converting video formats for Mobil devices and internet . but i am limited on how it save files. because flash vbideo files were made to run on a server side were you add your sound files in to match the flash video.

let me work on it i'll see what I can come up I don't make the files so big no one will download them.

Adobe decoder for me to convert files for mobil devices offers mp4 but when i use it ,.it does not include the sound files because its for mobil and requires server to run it