Cannot use Haiku 4.5 model with api key in GitHub Copilot plugin

I'm using the official plugin from Github Copilot, but cannot use the Anthrophic Haiku 4.5 model via my api key (in Anthrophic account). Just to be clear: I mean the api key in my Anthrophic account. I do not have github pro.

When I want to add my own model from Anthropic, I get an 400er error. More details in the picture (view from left to right). I am fetching the haiku 4.5 model from the curl command…