Digital Signature not working after form enabled Adobe Pro XI and Reader XI

I created a form with a digital signature field in Adobe Pro XI.  The signature field works in Adobe Pro.  I "saved as other" and "enabled more tools".  When the form is opened in Adobe Reader XI the security properties say signing is allowed, but when I click on the digital signature field I get a window labeled "Add Digital ID" instead of being able to sign.  Is there something else that had to be done to allow the form to be signed in Reader?  Thanks.