[TYPO3-dev] preview of new content-version does not work for extension :: versionOL does not use URL-Parameter &ADMCMD_vPrev[table%3A97]=101 ?

[Johannes Konert]

Dear experienced developers,
I try to make my extension versioning save; the backend-preview-stuff 
for editors on draft-workspaces works now, but if an admin for example 
produces a new version of a page-content-element directly on 
live-workspace it doesnt. There is a preview-button directly beside the 
version (in List-Mode in BE). Clicking this opens a new window with an 
URL like
http://domain.tld/index.php?id=35&ADMCMD_vPrev[tx_table%3A97]=101
where 97 is the original uid of the content-element and 101 is the new 
version (both on live workspace on same page)

But the "preview" page always shows the original content element.
- My extension does a SELECTquery without any excludeFields (simply 
asking for record 97)
- then the extension does a 
$GLOBALS['TSFE']->sys_page->versionOL($table,&$row);

which doesn't do anything (in this case).
versionOL is not using the URL-Parameter ADMCMD_vPrev, why?
Which API-Function does?
Even $GLOBALS['TSFE']->sys_page->versioningPreview is not set.
Bug?..or do I have to evaluate the URL-Parameter myself and fetch the 
newest version for preview myself?

Thanks for your short hints.
Regards
Johannes :)