Is it possible to use markers such as ###USER_name### with a TemplaVoila template? If this is not possible, is there an alternative?
(Deleted my question in comment, cause I realized what you want)
Markers for DirectMail can be placed in TV (they will be not parsed by TV) or even in some content element. They just need to be available in the rendered content before DM will take it for further processing. Preview your page which has to be used as DM template and make sure that there are markers like ###USER_name### visible (untouched).