increase volume of ac3 file

I have captured a mpeg2 file using ati aiw 8500 card under win 2k pro. The audio is incoded in mp2 format 48khz. i used besweet to encode to ac3 and tried the max gain feature to increase the volume but it didn't do the job enough. I am currently trying soft encode to reencode it to increase volume. Can somebody explain how i can do this?

Don't reencode to AC3. Keep the MP2 sound if you're making DVD or convert to MP3 if you're making DivX.

cant keep it mp2 

although the original a/v video size is 3.52 dvdit pe 2.5 won't let me author it even if i convert it to dd. says that project size is too big. and maestro won't except mp2 or the original a/v file. so in order to get it onto a dvd-r I must first demux, which i use tmpgenc mpeg tools and then besweet to convert the mp2 to ac3.this is the only way i know of to make a dvd compliant project. any other ideas on how to do this would be great.