Luther's sermon on Mary's conception, immaculate or otherwise, is also found in Latin here.
It begins on p. 360, which is about 3/4 into the book, if you are scrolling down.
(I notice that my old Latin suffices to analyze some of it, especially now that I've read the sermon about six times in German and in Matthew Carver's English translation--which should be published soon, we think. Having grown up in Bavaria, Latin was taught to me by sisters of the order of Mary Ward, ironically.)
There is also one more translation, which has been found, a kind of "triglotta", as Matthew Carver calls, it in German, Danish and English. Find it here. We have the sermon now in four languages!
See also my other post on the subject, with more relevant links and some discussion in the comments.
Sermon: Trinity 8 - 2018
3 hours ago