Digitally signing multiple pages of same document

I have Acrobat 7.0 Professional. Is it possible to digitally sign multiple pages at the same time - so that my digital signature will appear on each page, showing the same date and time? I thought you would do it by drawing a signature box and then right clicking and choosing the "duplicate" function and then choosing to have the signature block on all pages, but that does not seem to work. Am I doing something wrong? If not, and if there is no multiple page signing function, then what is the function of the "duplicate" commands that shows up when the signature block is right clicked? Thanks in advance for help on this perplexing issue.