Webmail not working with virtual website

Webmail does not work when I configure a virtual website, where the website files are not located in the 'default' location on the OS drive. Webmail only works when the default location is used. Additionally, the default website is a 'secure' (https://) website, of which I don't need. Apple Enterprise Support directed me to RoundCube.net where I did not find any information regarding my issue.

Does anyone know how to host a virtual website (files in Other Location, other than default Lion Server OS directory) and make webmail work?