IAX Trunk Outbound Caller ID limit


I have been running trixbox v2.8 for a number of years but I am now looking to upgrade to Freepbx. I have completed a fresh installation of Freepbx on a new server. Whilst configuring the new setup I came across an issue on the IAX trunk configuration screen. In trixbox under the ‘Outbound Caller ID’ option I can define unlimited amount of Caller ID’s but in Freepbx I am restricted to 5 only. Is there somewhere that I can increase this limit?