Do you live in Calgary by any chance? There is a SPED chapter in Calgary and you could contact them directly to answer your questions about certification and membership. Also, you can check out the calendar on their website for when and where they meet. http://spedcalgary.typepad.com/
Concerning the second part of your posting, SPED hasn't gained the foothold and recognition in Canada yet that it would like, so my best guess is that certification may help and certainly can't hurt. This may be changing in Calgary however, with companies such as AMEC, SNC-Lavalin and Worley-Parsons committing to putting all their pipers through the SPED training to gain SPED certification. I can say that I have seen the SPED training material and I find it to be excellent, so you won't go wrong by taking their online training. If your company is a SPED sponsor, maybe they'll pay for it. I know of many successful designers that have worked their way up through the ranks, so to speak, through a combination of experience and individual courses, just as you are trying to do. And, by and large, you'll find that Canadian engineering companies are very accepting of what you can do, not how you got there.
However, you will need educational recognition for certain jobs, to join your provincial technical society, or to work in the USA or oversees (unless of course you're fortunate enough to have other citizenship), and for these you'll need a minimum of a certificate from an accredited Canadian institute. So, I would also check out programs such as the process piping drafting certificate program available through the Southern Alberta Institute of Technology. http://sait.ca/pages/cometosait/academi ... appd.shtml
. This link is for the day program, but many of the courses are available through correspondence.
I hope this helps, and good luck.