How do I setup auto-generated coupon codes?
All you have to do is create a regular Shopping Cart Price Rule. Set it up with whatever discount or conditions you want.
Then set *Coupon* to *Specific Coupon* and check *Use Auto Generation*.8
That's all you have to do. You don't have to actually setup the coupon codes under Manage Coupon Codes. MageMail takes care of that for you.
Note: This feature is available since Magento CE 1.7 / EE 1.12.