How to avoid missing customer emails when account manager is absent

Hello,

here is the scenario...

1. Sales account manager for what ever reason (sick, accident and unable to set Out of Office) is not at work in the morning.
2. Also, he/she cannot access email and voice mail to let customers know that he/she is unavailable (like REALLY unavailable).
3. Customer request requires urgency; however, no one knows about it for 1, 2 or 5 hours or days.

Is there anything that can be done to avoid this?

We have exchange 2007 with OWA operational. However, owa does not have ability to setup forwarding to to the other mail box. Giving office managers/supervisors access to employee mailbox? We can do that (email is owned by our company) but then there is still privacy issues.

any ideas?

Andrei