Customization of replacement tag?

[tomoh]

Hallo there!

Knowing little and hardly nothing of php, I´m wondering if there´s a way of customize the { TEASER:alias} rep-tag so the output is editable in
"conf.template_default.inc.php" as one does for ex: row based navigation $template_default["nav_row"]["link_before_active"] = <some span class> ?

Tomoh