Try using the clipboard in Biab to "copy" the midi parts and see if it will also "paste" them in a new song.

Or,

Make a midi file of the riff and use "load scrap" in Realband to "paste" the riff in your song there. I know that will definitely work.

Go to file-load scrap, then select your midi file of the riff, and then use edit-paste to paste the data into a track in Realband.

Trax