It might be a little bit different here in Singapore.
I once contacted SureFire regarding replacement parts and they told me they do not deal directly with those who are located in Singapore - instead they asked me to return the product to our local distributor (Sheares) and ask them to settle the replacement issues.
Now the obvious question is whether or not Sheares will entertain you if you don't have a local purchase receipt. You can always call them and ask.
If of course you purchase your product from overseas to start off with, you could let SureFire know about that and see how they handle it. I do not have experience with such scenarios however.