Right Hand FIngering Labels for TAB

It seems that the right hand fingering (p, i, m, a) are only able to be added to standard notation notes. Is there a way to add them to TAB notes? I did already try just doing a Ctrl K to add text, and although it does work for the p, i and m letters, when it comes time to type 'a', it automatically turns to a capitol A (for the chord) and cannot be changed back to lower case.

Any help would be greatly appreciated!