I am looking for a PHP based messaging portal.
Client 1 logins to portal sends a message to Recipient 1 (they may choose from a drop down box)
Recipient 1 gets an e-mail stating there is an message awaiting for them in the portal (no part of the actual message is contained in the portal)
Recipient 1 logs in and see's their list of messages, along with archives, history of messages for Client 1 who sent the message.
Recipient 1 is able to make internal notes as well and attach them to Client 1 only.
Recipient 1 replies to the message and Client 1 receives an e-mail stating they have a message awaiting them in the portal.
Client 1 logins and sees their list of current and past replies, and is able to reply, archive, or simply read without reply.
Recipient 1 is able to login and see if they've logged in and have read the message or not (notification is not needed but if a option can be added for their choice it would be better).
This would need to be MySQL based and easily brand-able along with MySQL data being encrypted.
An installer would be nice in case of reinstall needed but configuration files, instructions, paths, permissions, etc would suffice.