Scanned copies of the actual Nuremburg documents are found here:
http://www.lawandreligion.com/nuremberg.shtml
Follow the link "installments" to get to the documents.
Hitler planned to do away with Christianity, including Catholicism, in the Third Reich. Catholic priests and nuns were sent to concentration camps.
The following link is a timeline showing that a Papal Encyclical was issued within 3 months of the beginning of the Nazi "extermination" program, and the means by which it was distributed:
http://www.humanitas-international.org/showcase/chronography/timebase/1937tbse.htm
The actual encyclical is found here:
While the Vatican did sign a treaty with Hitler in 1933, it did so based on Hitler's lies and false information Hitler provided. This is not unlike the situation with other major powers that also failed to recognize Hitler's intent until too late.
Pax,
Ruth