Are you using the British (ebay.co.uk) or American (ebay.com) sites to list?
The eBay Canada site (ebay.ca) (this one!) allows you to sell in Canadian dollars.
Which is slightly less important than you might think, because if your customer is looking at your listing from another site, she will see your listing in both her own currency (that is, the currency of the site she finds you on) and in the currency you listed in.
If you go to any of my listings, for example, you should see the asking price for most items in Canadian dollars, because we are here on eBay.ca and in US dollars because I normally list in that currency.
More important for Canadian sellers is that the ebay.ca site allows you to choose Canada Post services for shipping and to use Calculated Shipping for those products which are too large or too heavy for LetterPost/LightPacket shipping.
There are both a Simplified and an Advanced Sell Your Item form under Sell up at the top of the page.
The Advanced gives you many more options and is well worth using.