The preset will allow promotion to all captured pieces, or to a piece that is in the 'supply' set. So you should put all pieces you can promote to even when they are not yet captured in that set. The GAME-code generated by the diagram also contains an array ('promotab') that per board rank lists which pieces you could promote to on that rank. If both the normal pawn and the Berolina are in the set of allowed choices (and either have been captured or are mentioned in 'supply'), you will be allowed to select those.
A problem might be that if you allow both Pawn and Berolina as promotion choice, you don't only allow Berolina to promote to Pawn and vice versa, but you also allow Berolina and Pawn to stay themselves. Since the choice would make no sense on the last rank, where neither of these would have any moves, I suppose this is not a problem, but rather exactly what you want.
The preset will allow promotion to all captured pieces, or to a piece that is in the 'supply' set. So you should put all pieces you can promote to even when they are not yet captured in that set. The GAME-code generated by the diagram also contains an array ('promotab') that per board rank lists which pieces you could promote to on that rank. If both the normal pawn and the Berolina are in the set of allowed choices (and either have been captured or are mentioned in 'supply'), you will be allowed to select those.
A problem might be that if you allow both Pawn and Berolina as promotion choice, you don't only allow Berolina to promote to Pawn and vice versa, but you also allow Berolina and Pawn to stay themselves. Since the choice would make no sense on the last rank, where neither of these would have any moves, I suppose this is not a problem, but rather exactly what you want.