UTF-8 mailbox names

Hi! I am aware of the option in cPanel where you can set "UTF-8 mailbox names" (browse to cPanel >> Email Accounts and click on Manage next to the default email user to see if the UTF-8 Mailbox Names option). My problem is that I would like to be able to change the default setting for new accounts created (also this affects transfers probably). Where can I change the default setting for this? I cannot find it anywhere in WHM. Where can I set this? Thanks, Daniel