[RCU] just one identity

I've just installed the newest RC 0.7 and I'm trying to find a solution to my problem. I'd like to have the mail composing form without the possibility to change the From: mail address/header. How can I do that? Our customers must login into the webmail with their email/password and so I want to use the email automatically as the only option to the From: header without the possibility to change this header. I was looking into some plugins, read some doc, but found nothing usable. To try to hack to code is imho not the proper way, hope there must be a solution. Or am I missing something?

Regards, Tomas

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