Signature validation in Alfresco Share addon by Zylk provides an action for validating PDF files (CMS/PKCS7 Signatures), SAR (Sinadura Xades Format) and XML Facturae (Spanish Electronic Invoice Xades Format) files in Alfresco Share. The information of the signatures is detailed in edit properties form, presenting the different information about signatures like signers, signature dates and the information about certificates (timestamps, OCSP validation).
We are preparing with Douglas C. R. Paes a release for Alfresco 5.2 that will be published in some weeks (probably mid-end september), with Brazilian Portuguese translation and Brazilian certificates. I will update this card, so you will be notified. Stay tuned!