this feature was there in free version in early release (may be version 1.1 or 1.2 ). This plugin is almost a new plugin. Most of the code changes, So if you put early code also, that will not work, You have to write new code.
If you see support forum (both free and pro) you will see i write code for users too often. I try my best to support users.
If you need to send a copy of mail to sender i can write for you. This may not be included to main plugin, Also there will be no option to enable/disable this feature. also you will be needed php version 5.3+.
Let me know.