Per User Message Size Limit not displayed on Throttle screen

==== Required information ====
- iRedMail version: 0.8.7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MYSQL
- Linux/BSD distribution name and version: CentOS 6
- Related log if you're reporting an issue:
- ProVersion : 1.8.2
====

Hi the documentations states that there is a per domain and per user messages size limit on this web page:
http://www.iredmail.org/forum/topic1223 … tling.html

BUT my screen does not have it.

https://www.dropbox.com/s/i0yvh35dsqeyb … .16.28.png

How do I get this feature?