Over on the Catholic Answers boards a few people (including Protestants) are trying to determine the official position on Luther from a Catholic perspective. A Protestant poster stated, "Oh come, do you think that we are so stupid as to believe that what was declared at Trent wasn't directly put on Luther's head? Give me a break, his very most solid of beliefs were declared upon those who believed them to be anathema. Please."
Catholics don't have any unity on Luther, or how to understand the Roman Church's opinion on Luther. For instance, see my papers, The Roman Catholic Perspective of Martin Luther (Part One) and The Roman Catholic Perspective of Martin Luther(Part Two).
Exsurge Domine said that the Pope could, "without any further citation or delay, proceed against him to his condemnation and damnation..." Decet Romanum Pontificem spoke of Luther's "depraved and damnable purpose." It called for any of the faithful who were sympathetic to the Lutherans to shun them, so that they "may escape divine vengeance and any degree of participation in their damnation." It further declared concerning Luther and his followers: "...these and the other sentences, censures and punishments... we decree to have fallen on all these men to their damnation."
However, the great German Catholic historian from the Universities of Breslau and Bonn, Hubert Jedin held that Catholicism never condemned Luther by name at Trent, and that no official judgment on Luther exists by which a loyal Catholic is bound.
I leave it to better minds than mine to determine the navigation through such official statements.