Syslog message size

Hello! I want to change the default size of syslog message when it send to remote syslog-server. I find how it change for 10.x version.

 

http://support.f5.com/kb/en-us/solutions/public/8000/300/sol8306.html

 

 

But i don't find if for 11.x( I find the syslog-ng.conf, but i don't think that right way. Can you help me? Thanks!