in reply to Re: Setting syslog layout with log4perl
in thread Setting syslog layout with log4perl

Your first option is close but I think that the ".ConversionPattern" comes after "layout", so the second line should read: 
log4perl.appender.SYSLOG.layout.ConversionPattern = %-5p %C - %m%n

[download]

In Section Seekers of Perl Wisdom