"..does not illumunate when the Annunciator Test switch is operated..."
So, you checked it only with test switch?
It's because when test pressed for zibo it set the related zibo dataref to 1, not affecting SimVim dataref.
But it really works as you arm the SB.
The final goal is to make all systems work independently on the specific custom plane model as we did for many other systems already (so you don't need to "remap" them to the custom commands).
A bit later we will add the "test-ready" attribute for every assigned LED, as default it will be linked with "Test all annunciators", but also can be related to other "test" buttons (or not at all).
.."(for some reason..."
Yes, I know what for and which datarefs in b737 are used. :)