Due to my holiday obligations this one took a bit longer.
This piece is remarkable as in the middle section Rheinberger treats the chorale "Wer nur den lieben Gott lässt walten". So far there are only a Trio from the Monologues (http://www.contrebombarde.com/concerthall/music/6529) and a preliminary study for it (http://www.contrebombarde.com/concerthall/music/6526), which we would call chorale preludes. So this is the third. As in the monologue Rheinberger does not indicate the chorale.
I have added the piece to the playlist of the Miscellaneen.