[TYPO3-mvc] ajax plugin storagePid

[hannes]

Hallo,
I have following problem: I have configured a new extbase plugin which 
is called by an ajax request.
This request should return some data which i get from the repository. 
The problem is that the repository
dowsn't find any datasets, which i defined in the backend.
I suggest that the storagepid is not set correctly, but I don't know how 
to set it for this plugin?

I would be thankful for every help,
 Mfg Hannes