I have a Mac Xeon 2GHz - 3Gig RAM - Boot Camp Windows Vista 32-bit

I will be mixing audio for a film in 5.1 and would like to know what software to use. I'm used to Sony Vegas, but everyone is ProTools. In order to mix 5.1 with ProTools, you need plug-ins, and they are only compatible with ProTools HD ... So THAT'S OUT.

I already have 5 KRK monitors and an audio interface (RME FireFace 800)

My choices are:
  • Sony Vegas 8 / Sound Forge 9
    LogicPro 7
    Sonar
    SoundTrack Pro

Dolby Laboratories uses ProTools and said: "As long as you have all tracks saved as individual WAV files, we can load them into our system."

Being as how they only take Audio files (up to 400 tracks) Does it matter what program I use?