Luther: The Assumption Was a Settled Fact?

I listened to a few of Catholic apologist Mark Shea's webcasts on the Assumption of Mary. Mark made one statement that I would be very interested in having documentation for:

"For Luther the Assumption was a settled fact...indeed Luther's burial vault in the Wittenburg church on whose door he had posted his ninety five theses was adorned with the 1521 Peter Vischer's sculpture of the Coronation of the Virgin."

First and foremost, I would be extremely interested in which primary references Shea can provide from Luther in which Luther explicitly confirms a lifelong belief in Mary's Assumption. Saying "settled fact" requires proof. A quote with a context would be nice (and I would hope not to get one of those sparse English translations from a German source that no one has, particularly the person making such a claim). I have done a lot of research into this, so if Shea can pull the assumption out of a Luther-hat, this I'd like to see.

Secondly, as to Luther's burial vault, Shea explains in an old blog entry (edit: no longer available, but found here, and here):

"And, of course, problems with it constituted no difficulty for the Reformers, which is why Luther's tomb is decorated with a bas-relief of the Assumption. Indeed, objections to Mary are johnny-come-latelies on the stage of Protestant theology, as is demonstrated by Fr. Peter Stravinskas in Mary and the Fundamentalist Challenge."

This is the claim made by Peter Stravinskas:

"Most interesting of all, perhaps, is the realization that his burial chamber in the Wittenberg church, on whose door he had posted his 95 Theses, was adorned with the 1521 Peter Vischer sculpture of the Coronation of the Virgin, with the inscription containing these lines: Ad summum Regina thronum defertur in altum: Angelicis praelatia choris, cui festus et ipse Filius occurrens Matrem super aethera ponit. This "archaeological" fact would seem to speak volumes about Luther's final thoughts on the place of Mary in the life of a Christian."

This website makes an interesting counter-claim:

"If one believes Peter Stravinskas, it would seem that this inscription on [Luther's] heart is reflected in the inscription on his tomb. Stravinskas published a generally good article on 'The Place of Mary in Classical Fundamentalism', but I'm afraid he made one pious mistake: He maintains that the sculpture of the Coronation of the Virgin and inscription by Peter Vischer the Younger which is to be found in the Wittenberger Schlosskirche, where Luther is burried, goes with Luther's tomb. I wish it were so, but I'm afraid it belongs to one of the other tombs in the church. If you google for images of Luther's tomb (or Luthers' Grabmal), you'll see that it is the simplest little slab of stone rising a little out of the floor of the main church, a good distance away from the walls - no "burial chamber" at all. The German tour guide "Baedekkers Allianz Reisefuehrer Deutschland, 1991" mentions that "in the Schlosskirche there is a piece of art by Peter Vischer the Younger, who also created the tombs of Sir Hans Hundt and Prior Henning Gode." So if somebody out there could go by the church and let us know to which tomb this obscure "piece of art" belongs, I would much appreciate it."

And this website states:

"2. Epitaph for Henning Goeden
Directly to the right is located "The Coronation of Mary", a bronze plate created in 1521 by Peter Fischer the Younger, a founder from Nuremburg. A work of great aesthetic merit, the plate is the tombstone for Henning Goden, Jurist and last Catholic Provost of the Castle Church."

But, ok, let's for a moment grant that Luther's burial chamber has this particular sculpture. How in the world does this serve as proof Luther held a lifelong belief in the assumption as a settled fact? Mark, if you read this, please try an understand, lack of proof does not mean "proof". You must do better than a burial tomb, or stating something like Luther never spoke against it. Take these words to heart:

"But an argument from silence is recognized by all to be quite weak. It implies that one must have almost total evidence before demonstration is possible. If this is the case, one could argue cogently that there may have been airplanes in the time of Christ." Dewey M. Beegle, Scripture, Tradition, and Infallibility (Grand Rapids: Wm. B. Eerdmans Publishing Co., 1973), p. 178.