Acrobat Pro XI - can you apply digital certificate to certify Portfolio?

I used to be able to View-> Portfolio-> Cover Sheet and then certify the Portfolio with a digital ID. Now Acrobat hangs every time I try. 

Adobe support team may be working on it but it's difficult to tell if they are actually paying attention.   A friend also tried it with same failed results.   Can anyone get it to work or am I the only person in the world using Digital Certs to sign PDF Portfolios?

Here's background info on how to do it: http://help.adobe.com/en_US/acrobat/X/pro/using/WS396794562021d52e-7abb39ef12b34b0e1cd-800 0.html  

Acrobat Pro XI Version 11.0.07 on Windows 7