I watched the tut too… incomplete.
Complete your menu up to the point were the tutorial ends.
Render your AE created menu as a normal Viseo file that u can import, but for the buttons to work, export as Photoshop layers from AE… THEN import PSD into Encore.
Have rendered video in background and PSD buttons will be seperate.
I know this seems like a kind of broken description, but thats because Im stugglin through this as well.