The WT00Z-1 “Accessory Switch” is a fully independent z-wave device that is discovered and functional as a trigger. It’s basically an up/down trigger that has no inherent relationship to the “parent” WD500Z-1 dimmer. Here is a picture from the Rule Machine Capability Test - “Kitchen Desk 3W” is one of my WT00Z-1 accessory switches. It is instantly discovered as a dimmer switch by ST.
Ironically it was easy to integrate this ZWN-SC7 Enerwave 7 Button Scene Controller into Rule Machine which requires a custom device handler. The thread for setting it up is here. It was very easy to assign one of the 7-buttons on this device as a simple on / off toggle using a rule. The WT00Z-1 is essentially a single button (up/down dimmer actually) z-wave trigger.