How to do slow motion and fast foward in Vegas 7?

I know how to do it changing the number in properties but it keeps the clip to the same size ie. it will make a 30 sec clip if i do slow motion .5 it will only show the first 30 seconds instead of all 60...is there a way to keep it so it automatically does it instead of dragging it trying to make it perfect?How to do slow motion and fast foward in Vegas 7?Slowing motion is a beaut of an idea