[syslog-ng] Writing to a named Pipe

Hello, In my syslog-ng configuration I'm writing messages to named pipes which name is given dynamically by the $PRI macro: destination d_test { pipe("/tmp/$PRI.log"); }; All the possible PRI.log pipes were created previously with mkfifo. With this configuration the messages aren't being written to the pipes. It simply does nothing. Doing a strace on the syslog-ng process, it shows an error : open("/tmp/$PRI.log", O_RDWR|O_NONBLOCK|O_NOCTTY|O_LARGEFILE) = -1 ENOENT (No such file or directory) It seems that the PRI macro isn't being interpolated in the string. Any help?