Hi -
If you are shipping from Canada to Canada, I see no reason why you can't use our shipping insurance.
It looks like either way - if you use flat rate or calculated shipping, the shipping insurance option is still there for you to include it on your item.
The shipping insurance works the same for those in Canada as it does for those in the US. Offer the shipping insurance, your buyer pays you, the policy is created and you pay us.
Here is the page where you can see transactions, what you owe, rates, etc... http://www.auctiva.com/account/inssettings.aspx
Hope that helps!
Cara