How do I get Adobe After Effects keep my movie's 16x9 aspect ratio?

I have used After Effects 7.0 for a while, but I have been having an issue with aspect ratio. When I import my 16x9 footage (originally shot in HDV using the Sony HDR-HC1, then downconverted to DV upon capture to the computer, though still 16x9), and I select %26quot;DV Widescreen%26quot; for my composition type and pixel aspect ratio as %26quot;1.2%26quot;, when I go to have After Effects make the movie, using the MPEG-2 format, it won't export it in 16x9, it wants to use 720x480. So, if I change my pixel aspect ratio to square pixels and lock it to 16x9, then if I try to use MPEG-2 it won't work. I don't know what I'm missing; I realize that with 720x480 comp and 1.2 pixel aspect ratio, then 720*1.2= 864, which is 16x9, but none the less, the output is squished to 4x3. After Effects will do 16x9 with AVI, but that is far too large for DVD or web use. Any suggestions for 16x9 with MPEG-2? Thanks.How do I get Adobe After Effects keep my movie's 16x9 aspect ratio?contact their customer service for help.