Edit BO 'New Account' Page

[larissar]

I want to add a hidden form field to the new account creation form on the back office however I cannot figure out which .tpl file to edit.

 

The reason I want to add this field is because I want to completely disable new accounts being created in the front office by check if this hidden field exists (which would only exist in the BO form) and cancelling registration if the field is not detected.

 

I've tried simply removing the front office html so the form does not display but new accounts are still created so this is not good enough.

 

Any help would be greatly appreciated.