[TYPO3-ttnews] tt_news and backend field "layout"

[Jan Kornblum]

Hi group,

i want to use tt_content's backend field "layout" for tt_news / 
plugins:

$TCA['tt_content']['types']['list']['subtypes_excludelist'][9] = '';
$TCA['tt_content']['types']['list']['subtypes_addlist'][9] = 
'pi_flexform, layout';

As soon as i choose anything other than "normal" inside the elements 
"layout"-field, tt_news doesn't output anything any more. It even seems 
that the plugin isn't loaded at all and tt_news->main_news() isn't 
called...

What is wrong with my approach or how else can i make the 
"layout"-field usable with a tt_news plugin?

TYPO3 ist version 4.5.26 and tt_news is 3.4.0.

Grüße, Jan