[Typo3] changing locallang for css_styled_content with typoscript

[Xander Damen]

Hi,

I tried to change a label for css_styled_content with typoscript but I can't 
seem to get it working.

I tried:
tt_content._LOCAL_LANG.nl.label.toTop = Terug
plugin.tt_content._LOCAL_LANG.nl.label.toTop = Terug

Any ideas?

Thanks.

Xander