Tricaster .mp4 output back into Tricaster

[ej4 east]

I work on a Tricaster Studio and have used the .avi format to output my files. Although, I know .avi is high quality, I'd like a smaller file size. I've been testing the different outputs and have come to like the Apple Ipod .mp4 output. However, if my video requires more editing after I remove it from Tricaster in an .mp4 format, when I bring it back in, I get an image but no audio. I am thoroughly surprised that the Studio would give me the option of an output that I can't bring back in and edit. Are there any patches to this audio issue?