You can make your title in Vegas using the media generators and whatever else you want. Render this as a MPEG 2 DVD Architect video stream. You can create and render your menus background audio as well.

In your DVDA project you set this MPEG as the background of your main menu. There is a spot for setting audio too if you have any. You then drag your movies etc. onto the page like you normaly would when making a DVD. Since you already have the text labels rendered into the background files you can set the buttons to be image or text only. Then you can erase there contents making them blank. Blank buttons will have the "no text" message you are talking about. Drag these buttons over there respective text labels in the rendered background. When previewed these buttons will simply be invisible allowing your text to show through.

One thing you will not like is that with DVDA you cannot delay your button highlites. They show up right when the screen is accessed. So if you have text in the back ground that is moving too much or fading in it will look rather odd.

There are work arounds for this but they involve editing the actual DVD files after DVDA creates them.