[TYPO3] tt_news single view doesn't cache with realurl

[Georg Ringer]

Hi,

i got a strange problem and I am really wondering how to fix it.
The single view of realurl won't cache if I use the parameters of 
tt_news for realurl configuration.

this will be cached:
deutschland-tour-details.html?tx_ttnews%5Btt_news%5D=99&cHash=a1988497bd

this won't be cached:
deutschland-tour-details/article/weser-radweg.html

All I changed in realurl config is the following snippet and it occurs 
with the latest and previous version of realurl:
-----------------------
'postVarSets' => array(
   '_DEFAULT' => array (
	'article' => array(
		array(
			'GETvar' => 'tx_ttnews[tt_news]',
			'lookUpTable' => array(
				'table' => 'tt_news',
				'id_field' => 'uid',
				'alias_field' => 'title',
				'addWhereClause' => ' AND deleted=0 AND hidden=',
				'useUniqueCache' => 1,
				'useUniqueCache_conf' => array(
					'strtolower' => 1,
					'spaceCharacter' => '-',
					),
				),
			),
		array(
			'GETvar' => 'tx_ttnews[swords]',
			),
		),
   ),
),
-----------------------

There is no USER_INT, COA_INT at the page and otherwise it wouldnt get 
cached without the advanced realurl configuration either.

any hints?
many thanks
georg