http://www.canadavisa.com/canada-immigration-discussion-board/threads/pnp-pr-jan-feb-march-2016-applicants.396795/page-330
Good Evening
Please see this page, someone posted how the PPR email looks like.
On step 4 it's clearly stated that if you are unable to send your passport to Ottawa please email
CPC-CTD-Ottawa@cic.gc.ca so that we can send you instructions for submitting your documents to a visa office which is the most convenient for you. Please note that our office will not return passports to an address outside North America.
By chance, if you are outside of Canada and got the PPR then you can email them to send you new instructions to submit your passport to the visa office responsible for your home country.
and you can do the landing on your way back in Canada.
Hope that's helpful.