In the enhanced client (EC), you just drop the bandaids into a hotbar, and select "target self" or "target stored" (e.g. your pet) with a right mouse click (hint: if you need target self AND target stored, just drop the stack into two hotbars and change the selection, the system will store your choice). You then assign a hotkey, and it will take the bandaids from the belt or anywhere else in your inventory / paperdoll when you press the hotkey. Note that the built-in target self with bandaids macro doesn't work right now anyhow with the belt, also note that after dying and using the sacrifice skill, you have to open the belt once, otherwise the system doesn't find the stack. If you resurrect at an ankh or by a healer, the stack is oddly mostly found by the system, so you don't have to click anything. Also note that you have to use the same color of bandaids everytime, unless you want to drag and drop the stack of bandaids with the new color everytime into the hotbar.
Again, my comments are related to the EC, not sure about the CC.