Seeing as Zimbra 5 is out I would like to see also what new APIs are out. Is there any API doc? (it was not obvious to find on website, sorry).

We're heavy Zimbra users at my company and our Zimbra instance is hosted remotely by a separate company. So the APIs I need would be either remote ones (http, SOAP, XML_RPC, ...) or ones used in the browser (Ajax and script). Zimlets are cool but as far as I could see do not cover the needs below. Correct me if I am wrong please - an dpoint me at the doc that explains how to do it.

The areas we are looking to work with are

attachments: "saving" them to an API we specify rather than to the disk,

attachments: choosing the app that opens them (sometimes we want e.g. a specific js API to be called or a web page to open rather than the default app)

email signatures: can they be set programmatically?

contacts: can they be edited programmatically?

Thanks for the help.