Set default html editor roundcube

Hi all,

How to set default html editor when reply email on Roundcube 1.0.1?

==== 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 64bits
- Related log if you're reporting an issue:
====

Thanks