[syslog-ng]Using full hostnames

I'm trying to use full hostnames such as www.my.domain.com for both inside the log files, and also for the $HOST macro in the config files (for creating directories based on host). What options should I use to achieve this? I've tried a few different options, but I am only able to get either www or src@www inside the log, and the directories are always simply www. TIA, Andrew