What I'm saying is that pretty much any modern video editing software likely has DVD creation built into it, even many of the free ones that come bundled with computers.
I've not used Sony Vegas, but having just looked at their website, the latest version 12 has the following feature listed:
Professional DVD layout and design
Author menu-based and single-title DVD and Blu-ray Disc projects using preset backgrounds, motion menus, buttons, and effects. In addition to these presets, you can import your own layered Photoshop® (PSD) files for use as backgrounds, buttons, and graphics. Enable your DVD content to play back in a loop, hold, or time out at the end of a scene.
So you should have everything you need right there.
If its all a bit over your head though, perhaps look at some of the more simple pieces of editing software.