[TYPO3-english] wfqbe(Db Integration) hook preProcessQueryStructure only in BE?

[untangler]

Hi,

I want to use the hook preProcessQueryStructure as mentioned in the manual.

Is it possible that this hook is only touched in the backend?
In my installation (4.3.2) this seems to be so...

In the source I found this hook in class.form_generator.php and nowhere  
else.

Any suggestion?

regards
untangler