We arent allow to redefine the controls appearance in this version. Just redefine its positions or remove it if needed. This feature planned to next versions.

you may use next JS code on your page:

<script>
CalendarContext.prototype.todayControl = CalendarView.getControl("XXX", "today");
</script>


on your page to set the label you need. ("XXX" in example below)

if you use popup mode - this script should be placed below calendar tag on your page.

It seems that the given workaround is no more valid with RF 3.1.3
The following JS put before the rich:calendar tag works:

<script>
 CalendarView.getControl("XXX", CalendarView.toolButtonAttributes,"today")
</script>

Please consider looking here: http://www.jboss.com/index.html?module=bb&op=viewtopic&t=125663