The Missing Missa

In the early- and mid-1980s, I was part of a choir at Holy Trinity Church in Georgetown, DC, where I was able to learn many of the great choral works of Catholic tradition. It became the experience by which I have judged choral singing at any parish. Among other creations, I learned a Mass setting by Hermann Schroeder (1904-84), based on one of the Gregorian Masses. For twenty years I have searched for it -- a recording, sheet music, anything. Finally, I may have found it. Its title is the Missa Gregoriana, and an audio track of the Kyrie may be sampled here:

http://www.sacredmusicamerica.com/harmony/realaudio/kyrie2.ram (RealPlayer required.)

I'm still looking for a complete recording of the setting, as well as a copy of the sheet music for my reference library. I've been on Google, I've been to Amazon. No luck.

Any ideas?