I have experienced a situation where I create a song in BIAB /RealBand / PowerTracks in which the song is finally to my liking and I am ready to render it to a compressed MP3 format. While listening to the rendered MP3 song I discovered that the ending cuts out about ½ to 1 second prematurely.

To correct this you have two choices (there may be more):
I open the song back up in RealBand (or PowerTracks). If your song ends with a cymbal crash, select the drum track and then the PIANO ROLL. Find where the cymbal crash is on the PIANO ROLL and drag it to the right about 2 more measures. What will happen when you render the song again is the ending will have a nice long and faded cymbal crash.

Still in RealBand or PowerTracks, if your song does not end with a cymbal crash I make a separate AUDIO TRACK available. I go to the end of the song, about 3 measures before the end and RECORD AUDIO (WITH MY MIC MUTED SO NO AUDIO IS RECORDED) and stop recording about 2 measures past the end of the song. What will happen when your render the song again is the songs ending will be extended past the last sound that of the instruments.

If anyone has other ways to extend the end of the song, please feel free to do so.
Credit for this information goes to Multitracker as he pointed this out to me in the forums.

I hope this helps.

Mark