How do I lower the playable pitch on a Tampani roll one more note?

Hi all. I am using a pitched Roland Timpani Roll soundfont and it works fine, except ... The lowest note it will play is a C2 note. All notes played below it are silent. I need the sound to drop down one more note, to a B1 note. I've tried to do so in the "Staff Part/Properties" menu by changing the "Usable Pitch Range" from C2 to B1 in both Amateur and Professional fields, but the note will still not sound when played. I then opened the Soundfont in Polyphone but found no place in the menus to edit the pitch.

Help! Can I lower this soundfont one more note to a B1? I tried to enclose the file here but this menu will not let me. I can email it to you if you wish.