Certificates no longer work for signing when moving to Acrobat XI

Hello,

At my organization we have vendor-supplied certificates (x.509 v3) that we use to sign PDFs.  These certificates function correctly with Acrobat 7, 9, and X (mix of XP and Win7).  When attempting to sign a PDF in Acrobat XI (Win7), an error is reported by the Windows CSP: "The requested operation is not supported.  Error Code: 2148073513".

I also have some certificates generated in-house that do not result in this error, and sign correctly with Acrobat 7, 9, X, and XI.

My guess is that some property of the vendor-supplied certificates is not playing well, and that it must be some difference between the two.  The vendor certs have about 10 extensions, mine has 2.  I've pasted a dump of the additional extensions below; all other details appear to be shared.  Key size is 2048 for the vendor, 1024 for in-house.

Thank you!

Certificate Extensions: 10

    2.5.29.15: Flags = 0, Length = 4

    Key Usage

        Digital Signature (80)

    2.5.29.32: Flags = 0, Length = 13

    Certificate Policies

        [1]Certificate Policy:

             Policy Identifier=2.16.840.1.114027.200.3.10.2.1

    2.5.29.17: Flags = 0, Length = 1a

    Subject Alternative Name

        RFC822 Name=xxx.yyy@zzz.com

    2.5.29.9: Flags = 0, Length = 15

    Subject Directory Attributes

        Entrust User Role=161

    2.5.29.31: Flags = 0, Length = 16d

    CRL Distribution Points

        [1]CRL Distribution Point

             Distribution Point Name:

                  Full Name:

                       Directory Address:

                            CN=CRL281

                            OU=Commercial Private Sub CA1

                            OU=Certification Authorities

                            O=Entrust

                            C=US

        [2]CRL Distribution Point

             Distribution Point Name:

                  Full Name:

                       URL=http://comprivweb1.managed.entrust.com/CRLs/EMSComPrivCA1.crl

                       URL=ldap://comprivshad1.managed.entrust.com/ou=Commercial%20Private%2 0Sub%20CA1,ou=Certification%20Authorities,o=Entrust,c=US?certificateRe vocationList;binary

    2.5.29.16: Flags = 0, Length = 24

    Private Key Usage Period

        Not before=Thursday, September 27, 2012 2:07:29 PM

        Not after=Monday, November 03, 2014 1:37:29 AM

    2.5.29.35: Flags = 0, Length = 18

    Authority Key Identifier

        KeyID=d6 57 4d cb f4 e9 cd 6a cb 67 b4 ba 1d cf 10 d3 8b d6 2c 99

    1.2.840.113533.7.65.0: Flags = 0, Length = c

    Entrust Version Info

        Entrust Authority Security Manager Version=V8.0

        Key Update Allowed=Yes

        Certificate Category=Enterprise