We sent my PA's Sched A through registered mail with tracking. A week later, we called CIC and confirmed that Sched A (IMM 5669) was attached to our file. At that time, we are still waiting for the PCC to come in but they already forwarded it to the local VO even without the PCC. So as soon as we received my PA's PCC, we emailed it to them and we got a reply two days later that it was received at attached to our file.
Just a note, their response time is not consistent to everybody else sending an email directly to CPC-M. I have read on other threads that some are getting a generic reply but some are getting quick responses too. Maybe it's just my luck this time. You can mail them your docs to the same address where you sent your application, at least that's what the agent told me when I called CIC. The addresses can be found on the document checklist, in my case - outland sponsorship IMM 5533. Make sure to use mail with tracking # so that you know when they received it. Also, when you choose to mail it, you will not get a response that they received it, you have to call them to find out.
