Honeybird.....you really should wait until you get the b-file number from the Visa office before sending anything else off. Yes, they can probably find the file with the client # you got from the sponsorship approval letter, however it would take them longer to find it and possibly slow things down.
About 2 weeks after I was approved to sponsor, I sent off an email to the visa office our application was sent to just telling them that all I wanted to know was whether or not they received the application for PR from Mississauga. I didn't expect a response, but 17 days after I sent the email, they emailed me back and in that email they included the b-file number.
Hope this helps