On the ADVANCED seller form under International Shipping there is Choose Custom Location and you can use it more than once. But it doesn't differentiate between Malaysia and Singapore (or Vietnam or New Zealand).
However, if you use Calculated Shipping then your buyer, where ever she is, will see the correct Shipping and Handling.
This only works if you are in Canada and listing on eBaydotCA.
Calculated Shipping is attached to the postal system of the national site.
BTW, the advanced form also allows you to list in either Canadian or US dollars.