I think, I am in an almost similar situation like you. I have sent my passport for visa issuance purpose to CHC, SIngapore by FedEx. I have done my re-medical on 9th May and sent my passport on 22nd May'2012. But, I did not receive any email from them yet.
It seems like they send that standard email to everyone who are in this situation, right?
After how many days of your passport sending did you get that email of your visa confirmation? could you please tell me?
I think, registered mail takes a bit longer. I am trying to figure out how can I use FedEx to carry my passport back to me. Any suggestion would be well appreciated.
Best Regards,
Rakib