Trying to "share" a Gmail account with my assistant. Help!

I use Google Apps for your Domain to run my small business and I am trying to configure my Gmail account on Google Apps to allow my assistant to “share” it.

I do not mean I want to share the full login credential.

My goal is merely that any messages that comes in for me:

1) Will appear in my assistant’s inbox (seems forwarding accomplishes this)

2) Can be replied to by my assistant in my name (Gmail allows me to change the send from address and this is working)

3) And the reply or whatever action is taken by my assistant is reflected in my inbox. This is the part I can’t figure out.

When my assistant replies to someone in my name, on a thread that originated in my inbox and was forwarded to my assistant’s inbox, I would like that reply to be associated with the thread in my inbox.

As far as I can tell, Gmail does not have an auto-bcc capability, so that plan is out.

Any ideas? Very much appreciated.