Harmonyhub: How to make such an switch switchable by Siri/Alexa?

I have a Harmony Hub which is connected to OH2; also I’ve installed the openHAB-Skill on Alexa and both works flawlessly - except one thing.

I want to make certain devices switchable by voice, but I don’t understand how to configure it.
Here’s my item:

String HarmonyHubWZTopf "Topfield" { channel="harmonyhub:device:Wohnzimmer:14363516:buttonPress", autoupdate="false" }

And here’s the definition for the switch in my sitemap:

Switch item=HarmonyHubWZTopf label="Power" mappings=[PowerToggle="Power"]

When I wanted to make e.g. a light switch switchable by Siri and Alexa, I just added “[Switchable]” to the item definition - done. But this doesn’t work here as the item only holds a channel definition but the key being pressed is set in the sitemap. And this doesn’t work for the voice girls in my house.

Any idea to solve this? Thanks!

Found this here: