Domain Mapping – Sub directory to Domain

Hi,

I have no success in domain mapping on a subdirectory Multisite install.

Right now there is a redirect from http://www.kompetenzenbilanz.at to https://www.helene-cuenod.com/kompetenzenbilanz

What I want is to keep http://www.kompetenzenbilanz.at in the browser field. Is mapping possible with subdirectories or does it only work on subdomain installs?

Thanks for you help!