You need set the number of bars from 1 to 30 (next to the tempo control). In the box to the right of where you entered 30, you can set the number of times that you wish the song to play through.
If you then go to Edit-> Settings for this song, there is a box labelled "Tag exists". Check this box and go to "Tag jump afetr bar #" enter 31, which is the bar after the main parts of your song. You can then add the last few bars.


Cheers,
Keith