First Vegas is not a "burning" app. You will need a DVD authoring or burning program (such as DVD Architect)
In Vegas you "render " your video out to whichever format you need depending on what you are going to do with the movie.
If you are going to "burn a DVD I would recommend an MPEG2 video and AC3 audio file.(For DVDA)
Your apparent reason for splitting the file (since you mention 4.5G) is to be able to fit it on a single DVD. You could use a DL DVD but people seem to be having problems with them. By adjusting the bitrate when you burn you can easily fit 2 hours on a DVD with reasonably good quality. If you need more length than that you can experiment with lower bit rates and depending upon the footage you are using it may or may not be acceptable.
Terry
I am trying to split an AVCHD file that renders into approx 13 gig. I used vegas 8 premium to render and was trying to get sony DVDA 5 to burn the project. When I first download it from my HD SR7 sony the Sony handycam utility calculates the number of disk needed and them burns one time, but only one time.
I'm looking for something that allows me to do the same thing after the files have been transferred to my hardrive.
BMSS