Added parts not exporting from score

I've been working on a score for a while, and I think I started with the 'jazz combo' template. I decided to add bari sax. The programme adds the stave to the score, but does not create an additional page for the bari part. And when I export the parts, all the parts that were in the original template export OK, but the bari part does not appear. Can anyone suggest a work-around please?