purchase order through External Send to include a CC address

Does anyone have any idea how to get the e-mail of a purchase order sent through External Send to include a CC address in the e-mail?

I have searched the forum and found a few questions regarding sending a purchase order to more than 1 e-mail address using external send, but not solutions.

We have got this working to send to the vendor, but the purchasing manager won't use it until we are able to cc the purchaser into the mail. This is to allow the purchaser to keep track on what has been sent. It seems like an obvious thing to want to do. Is it possible in standard SAP? If not, where should I start to get this to work? Is there a customer exit or another area of code somewhere that I can change to trigger a second e-mail. Alternatively can I run this through workflow somehow?

Any suggestions will be greatfully received and rewarded.

Thank you

Karen