Add page to document after signatures have been added.

In using Adobe Acrobat 8 Pro, I was able to add a page to a document after we had added signatures to it. This is required as we sign documents, send them to our client, they add their signatures and send back the page which I then add to the full document, therefore having all signatures in the one document.

In Adobe Acrobat XI I have found how to add a page but if the document has signatures in it the option is greyed out. How can I carry out this task in this version of Acrobat?

Elizabeth McIver