How do I format a related date field to DD-MM-YY

Thank you for your advice and help in advance.

I am using document templates to pull together fields from the RLI module as well as some related ones. The field below is from the module 'Issues".

I want to return the deadline_c field in the format of DD-MM-YYYY but I must be misunderstanding the structure. I used this for {!date format='DD-MM-YYYY'} and it worked.

{!formula value='related($is_issues_revenuelineitems_1, "deadline_c” format='DD-MM-YYYY')}

Works but shows the format as YYYY-MM-DD

{!formula value='related($is_issues_revenuelineitems_1, "deadline_c”)}

Again thank you for any help in advance.

thanks

Jay