It is a matter of choosing a music font (e. g. Jazz) for the accidental, rather than a text font (e. g. JazzText).

Actually, I have the same problem, and something screwy is going on in the code.

With Chord Suffix Font set to Broadway Copyist Text, Finale Copyist Text, or JazzText, I get "G7(B5)"

With Times New Roman, it's "G7(b5)" 

But then, if I select "Jazz" as the Chord Suffix font (which gives a lowercase "b", but screws up all the other Suffixes), THEN select Finale Copyist Text as the Chord Suffix font, the chord symbol (and all other chord symbols) show correctly.  If not done in that order, it reverts back to an uppercase "B".  

There's obviously something going on in the code that a programmer needs to fix.  In the meantime, that's my workaround.  Hope it helps.

Bill Sheperd,

This is a misunderstanding.

The font change is done in

Document menu > Document Options > Fonts > Chord

To get an accidental instead of a text font letter, change the font for accidentals (= Alteration), not the font for Suffix.

If you like, you can change the font for Suffix.

The font change will affect all new suffixes you create.

Already existing suffixes (as seen in the Chord Suffix Selection) will not be affected.