AW76:
I checked and the letter requesting a signed IMM5406 was sent to my wife, not to me (sponsor). So your IMM5406 will be sent to your wife in Seoul.
Rather than wait for Seoul to contact you, you might email the Canadian embassy there, citing your receipt unmber or Client ID # (if you have one yet). Explain the situation (brieflyl they have very little patience I find), and ask if your wife could mail the signed IMM5406 now, letting Seoul add it to the file when it arrives from Mississauga.
Seoul will give you one of three possible answers:
1) No.
2) Yes.
3) A canned response saying "Please refer to our website where everything is explained very well, and never bother us again with your petty questions. It is Christmas season, and we have many glamorous parties to attend, at taxpayer expense!!!!"