Hello Luis!
I'm from Manila but I'm guessing we have similar procedure in paying the RPRF because our apps are being processed outside of Canda. I looked for the link for your VO, and you may want to read the procedure in paying immigration fees here:
http://www.canadainternational.gc.ca/mexico-mexique/visas/fees-frais.aspx?lang=eng
Take note of these:
1.Current applications: If you are paying additional fees for an application currently being processed at the Canadian Embassy in Mexico City, the payment (certified cheque or bank draft) must be attached to the letter from our office requesting the additional payment.
2.(Right of Permanent Resident Fee - RPRF) CAD 490 OR MXN 6,300
Hope this helps!