The answer EDRi member DFRI received today was not signed by anyone but the sender of the email. Neither did it contain any ACTA documents.
The Commission argues that: "The question of the Court to the Commission, being a procedural document, does not fall within the scope of Regulation 1049/2001 as Article 15(3) of the Treaty on the Functioning of the European Union (TFUE) specifies that the Court is only subject to obligations on Transparency when exercising their administrative tasks. This has as consequence that the document itself can't be disclosed by the Commission."
Email from European Commission refusing disclosure of ACTA
documents (19.06.2013)
https://www.dfri.se/wiki/ep-acta-docs/EC-response-2013-06-19.txt
Email from European Commission extending deadline (29.05.2013)
https://www.dfri.se/wiki/ep-acta-docs/EC-extending-deadline-2013-05-29.txt
All ACTA documents @ DFRI website
https://www.dfri.se/wiki/ep-acta-docs/
(Contribution by EDRi member DFRI - Sweden)