Total Commander doesn't use Explorer icons because it has nothing to do at all with Explorer, so why should it use its icons?
You can change the default icons in buttonbar to your liking and I bet that there will be a better solution for the drivedll soon, at least I hope so because right now it looks like a patchwork, not a serious concept.
With a resource hacker you can change default TC icons and drivedll as well, it's more complicated than to change icons in Explorer but that's the price you have to pay when you use TC. It's a great program with an antique GUI. Nice looking icons just won't fit.

Icfu