User Profiles property as search refiners

SharePoint Online:

I have a requirement to refine people search results based on sills. We want to sue the default property SKILLS. I confirmed the property is available but is set as not refinable.

We are trying to setup a managed property using the unused MPN RefinableString00 and map it to the skills property but for some reason the skills property isn't available to be mapped.

Is this an unsupported scenario? If not how can we achieve this?

Daniel

daniel