The visa-office specific guide for CHC-New Delhi is the only one I've seen so far that provides info for the self-employed. See the checklist, p. A-4 of the Visa office specific forms for New Delhi.
http://www.cic.gc.ca/English/information/applications/skilled-mission.asp
"If you have experience as a self-employed person, provide copies of:
•business/company registration documents,
•proof of business conducted with clients (invoices, bills, client references)
•balance sheets,
•income tax returns, and/or
•proof of your licence to practice (if you are a private practitioner)"