Thanks, qinsoakedboy! I sent them an email last night. I'll let you know what they say.
I also went out pedaling on my wife's bike to see if I could find the pieces, but no luck. Baseline Road looks a little too clean; I suspect a street sweeper came by and took my pedal parts.
I might try a store here in Ottawa called "Ottawa Fastener Supply", because they have just about every style of nut and bolt made by mankind. The inner shield is just decorative, really, but the outer shield is all packed full of grease so I suspect I don't want to bike around without it securely fastened to the pedal.