There are several situations where Aliasdomain with redirect aren't the best solution.
- Different SSL for Aliasdomains than Main-Domain
- Multiple domains on one website but in different folders must have different document_roots e.g. because of the running application on this domain.
To solve this both problems it would be very nice to have vhosts for aliasdomains like already available for subdomains.
Additional Info (german) Another guy who already had the same issue: http://www.howtoforge.de/forum/installation-und-konfiguration-12/ispconfig-3-vhost-verhalten-2062/
(I'm already working on this issue and will soon use it on my servers - so if there are other guys out there who would like it, please vote for it - I will suggest the changes anyway)