is there a way to configure Webwork in such a way, that bounces of undeliverable email (a typo in student's address, for example) would be delivered to that section's professor's address or to the address given as From: in Email tool? Currently all the email messages leave Webwork with Return-Path address set from smtpSender in global.conf. smtpSender value seems to be inherently global, as it can't seem to be overriden from course.conf. I guess there are some design considerations for this as I can see that throughout Webwork code the 'from' variable is initialized from global smtpSender, while real sender addresses are only used for the 'fake_from' to Mail::Sender.
This would be a nice feature to have but it will take a fair amount of development including some understanding behavior of the smtp site to accomplish. I don't see it being high on my own priority list.
If you or someone else can devise a robust and secure way to accomplish this (that doesn't interfere much or at all with current behavior when that is preferred) then I will be glad to include it in our code base so that others can use it.
We can offer some support, for example by making a development branch available in our svn (talk to Jason Aubrey about this) and of course we're happy to offer consultation on those aspects of this behavior that we are familiar with.