I'm trying to configure Zimbra to meet our needs. What I am not able to do so far is to bind a specific signature to a delegate account.

An example:
- john.doe@domain.com
- jane.doe@domain.com
- shared.mailbox@domain.com

I want that John and Jane see the shared mailbox "Inbox" and "Sent" directories. OK.
I want that John and Jane are able to SEND AS shared.mailbox@domain.com. OK using "delegate" function in the shared.mailbox@domain.com web ui -> preferences -> account
I want that John and Jane, when sending as shared.mailbox@domain.com, automatically have a different signature. NOT OK. I can't assing a signature to a "simple" delegation. I can only assign it to an identity.
If I create a new persona called shared.mailbox@domain in John and Jane web interface, I can assign a different signature BUT when I try to send a new mail, in the drop-down list I find THREE account:
- user account -> with personal signature automatically assigned
- persona account -> with specific signature automatically assigned
- delegation account -> without a specific signature.

How can I simply have 2 account from which I can send mail with a specific signature?

Thanks in advance