We have a Work Centre 7556 that we got in January. When we print a booklet from a PDF file and tell it to staple, it works. When we print multiple sets of the same booklet and tell it to staple, it staples all of them together. Customer service says it's a known issue with Adobe, starting with Adobe 8, but why only when you print multiple sets? We had a Work Centre Pro 55 (?) before we got this one and it worked fine. Any ideas?