WordPress in root, a subdomain should be redirected to a specific folder

Hi,

i have wp installation running under http://www.example.com and example.com and wordpress is in the root folder.

Now i have setup a subdomain like xyz.example.com, which should point to specific folder, i.e subdomain xyz.example.com should point to folder xyz.

I tried to modify the .htaccess file, but i can´t figure out what´s wrong. It always redirects me to example.com or states internal server misconfiguration.