Apps :: Virtual Users in pureftpd

I want to setup a FTP-server with pureFTPD. Normal users works fine but is not useable for strangers. I already check a lot of URLs and I think that VIRTUAL USERS is the solution. I tried a lot (adgroup, useradd etc) but unfortunately it didn't work. Is there anybody who acomplished it and share this information with me? All hints appreciated !!

original here.