Thanks for your very fast response!
I did not mention it but had previously played with plugin management and set the ITB plugin to load before other parsers ('Hider', for example, is another parser plugin I use) as I had already suspected that the order of execution could have some effect on the plugins. It did not make ITB work though.
BUT -- guess what! -- installing the 4.99$ professional version made it work.
I guess that the free version maybe is no longer properly maintained and is not up to par with current CB / Joomla releases?
Anyway, the Pro version worked right away using my same sample code, as I did not change anything else.
Now that was 5 dollars well spent!
Thanks again,
Sebastian