I have resorted to sending a message from his mailbox, when folks do not even open their mail from me.

At least it gets opened and I can see the return receipt. He knows my tactic and knows I only use it as a last resort. Attention getter if you will:) However, I try not to involve him since his e-mail box receives alot of mail and his time is valuable. One less for him to open in the box is always best and I try to avoid it as much as possible.