Foren / Cotonti / Support / Shorter date

Can these callbacks also be used with custom extra fields?

I use a custom field named {LIST_ROW_AGENDADATE} for date/time in a list, and i've tried a callback like this:

{LIST_ROW_AGENDADATE_STAMP|cot_date('date_fulltext', $this)} 

but this results in the default time (Thursday, January 01, 1970) instead of the date that is set in the custom field.

Added 2 days later:

Anyone?