[TYPO3-ttnews] Add More Link when String is found

[undkonsorten]

Hey List!
I want to add a more tag like used in Wordpress.
When you add a special string (eg. <!--more-->) to the bodytext, tt_news 
is supposed to display the bodytext up to the <!--more-->, hide the rest 
of the text and add a more link instead.
If no <!--more--> is entered, the whole text is visible and no 
[more]-link is added.
I made several attempts to realise this via Typoscript, but failed. It 
should be possible with eg. ".split" or ":= replaceString", not for me 
though.

Do you have an idea or some code for me?

Thanks,
Botho