In the Project Properties on the left, left click on your intro and select Set Start Item. Check the End Actions on your intro in Media Properties and verify intro is linking to the first menu.
"Now, I want a smooth transition from the intro to menu page:)" - oh yes!
I am listening to this one. I have just finished an intro Play Once Video that ENDS with the image OF the User menu. Transitions to it? I had to "wing-it" back and forth until I "nearly" got it the way I wanted. I hope to hear a better solution.
You could use your intro video as the background to the menu, rather than playing it first. You could then have the thumbnails, or whatever menu items you have, appear when the play reaches the appropriate point. You can do this by setting the menu loop point at this position.
You can make a smooth transition from your intro into the first menu but you have to make some changes mainly th eintro becomes part of the menu. First, your menu has to be a motion menu the with intro and menu encoded a 1 progressive mpeg with a transition of your choice. You need to set a chapter point at the beginning of your menu so you will get an I frame at the starting point of your menu. This will be the loop point for your motion menu. Create your menu buttons in Vegas and use highlight masks in DVDA. Set your movies to link to the loop point in the menu on completion.
I went one step further and added menu exit video. I added a third or end video to the motion menu video, It has and intro, menu, exit compiled as 1 progressive mpeg wiht chapter points and the strat of the menu (loop point) and the start of the exit or end video. Again make the the mpeg encoder is to place an I frame at the chapter points. When I setup the menu section I set the end of the menu at the start of the end. Whe you make a selection on the menu it links to the end and then to the vidoe selected. Believe it or not but I discovered by making the end part of the motion menu video the transition to end was smooth.
This is a clip from a menu I made for the movie "Amadeus". It's made from a single image cut into layers that I "turned on" over time. I imported this video with it's accompaning music to DVDA. Where the video zooms in, I set the loop point (where the music changes too) and the "Play Movie" and "Scene Selection" buttons then appear.