Tracey, a couple of points:

Maltitol is (legally and technically) a form of carbohydrate; it's a "nutritive sweetener" meaning it has calories. It's reportable as carbs (FDA) and is digested as such, just more slowly and further down in the digestive tract than sucrose (which is why the calories and glycemic index are somewhat lower). NOTE: larger quantities (presumably more than 1 'serving') can do do cause gastrointestinal distress (i.e., diarrhea) for many people. If you still want to use it as a sugar replacement, search for isomalt; I think I've seen an isomalt or malt syrup in Asian groceries.

Sucralose is the chemical name for the Splenda brand non-nutritive sweetener (negligible or no calories). No carbs except for those found in the carrier/filler (such as in spoon-for-spoon or packets) which is usually a maltodextrin or dextrose base.

I find the Sucralose/Splenda to be about 90-95% as sweet as sucrose or table sugar. I find the isomalt about the same in sweetness.

Hope this helps you out.