I looked on the BC Vital Archives page (http://www.bcarchives.gov.bc.ca/textual/governmt/vstats/v_events.htm#indexes) and found the there are two listings of marriages for a Frank Peterson and Ellen in 1911.They are:
If you put a query out on either this site or subscribe to the BC Mailing List - it's free and located at: http://www.rootsweb.com/~jfuller/gen_mail_country-can.html#BRITISH-COLUMBIA-CANADAhttp://www.rootsweb.com/~jfuller/gen_mail_country-can.html#BRITISH-COLUMBIA-CANADA I'm sure you will find someone who can send you a photocopy of the marriage registration.They usually name the parents of bride and groom.For someone to get a photocopy for you from the Main library at the Vancouver Public library it will only cost .40 cents for the photocopy (some people may even charge postage which is understandable.) If someone can help you from elsewhere in BC it should still only cost the fee of photocopying and postage.I know this because I used to get photocopies of the marriage registrations when I used to live in B.C. and it only costs photocopying charges - even though I used to see people charging $5 or $10 for a copy - remember they're only paying .40 cents!!!!
I would recommend trying the BC Mailing list - I've seen people offering to do these kinds of look ups for free.Good luck.