Register Event Participant-Uncheck Send Confirmation and Receipt by default

[madura]

Hi,

When i Register a event participant, the Send Confirmation and Receipt remains checked, how do i make it unchecked by default?

The extension for this is not supported in the version of CiviCRM (4.5.7) we use - https://civicrm.org/extensions/prevent-sending-event-registration-confirmation-back-office/version-11

Is there a way around it? Any help would be much appreciated because I have been trying to do this for ages

Thank you!