Please see a pic of the original sheet music below. I am attempting to re-create it in Finale. 

Because of the tremolo, the original sheet music included 5 beats in this measure. The time signature is 4/4. I would like to write the tremolo notes as eight notes to prevent the extra beat. Here are my questions:

1. How do I enable a tremolo between A and B in Finale?

2. How do I add a fermata in addition to the tremolo? In my attempts, it seems that Finale only allows one or the other.