[TYPO3-dev] Caching additionalHeaderData of USER plugin

[Martynas M]

Hello,
In USER plugin I am trying to put some js/css files by
$GLOBALS['TSFE']->additionalHeaderData['my_ext']
and they are not cached if there is at least one non-cached object in
the page (USER_INT, COA_INT ...).

When hooks
$this->TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['contentPostProc-cached']
are executed - in header there is
<!--HD_c4328e5578ca87de3d1a8565f93d289b-->
 so nothing to cache for my USER extension.

Strange thing is that <!--HD_c4328e5578ca87de3d1a8565f93d289b-->
appears only when there is at least one non-cached object. If there is
no non-cached objects, my extension header part is properly cached.

Same problem is discussed here but without success:
http://lists.netfielders.de/pipermail/typo3-dev/2009-January/033105.html

The reason why I need to cache header parts is using CDN:
in hook contentPostProc-cached I move css/js files to CDN and replace
href/src of css/js.

So simple question: how to cache additionalHeaderData of my USER extension?

Martynas