Not true - they do thru check bags for AC to AC seperate tickets, just not AC to other airlines seperate tickets. (http://www.aircanada.com/en/travelin...t/checkin.html)

The wording on the Certs does say valid for origin to destination upgrade including connections, so although it'd probably be a hassle to notate the second booking with remarks that the cert has been lifted, it should feasibly be able to be done AFAIK. Stand to be corrected.