Exif Tags Rating (& RatingPercent) not synchronized

[U.H.M.]

Dear DigiKam experts,

I have some hundreds of pictures with rating tags from windows.

Windows Rating
Windows Rating Percent

I'd like to have digiKam 2.5 to use this for the 5 star rating. But it doesn't work ....
It works with several other programs .... so I'm sure the Tags in the file are OK ...

I have the synchronizing options of settings -> configure -> metadata on ...
But after giving new ratings in windows, these are not shown as digikam rating, but visible as exif tags!!!

Whats wrong ???

Thanks for your reply in advance,  greetings, UHM