As you're in Germany, you need this card.
https://www.ebay.co.uk/itm/PCI-2port-SATA-Controller-RAID-0-1-p849/330755970915
I ordered 2 of this cards and they ship me 2 of the 4 port cards with sil3114 controler .
sil3112 ist soldout i think ..?
No It shouldn't.
Sil3112 it's not enough. The card needs a Mac Os 9 compatible EPROM.
Nope, even more. All, but genuine SeriTek cards and the factory reference cards directly from SImage have a faulty part on the PCB.
That part will prevent the proper wake-up on some of the G4-s. The G4 will go to sleep - but never wake up, regardless of the O.S.
As far as I recall, the worst was the "Quicksilver" (pre-mirror door) G4. The problem was with PCI timing.
The only good cards working on all involved Macs are the genuine SeriTek and the genuine factory reference cards from SImage.
I don't remember, the later were sold to the general public.
Both SImage 3112 and SImage 3114 are a risky choice, unless from FT or SImage.
I can imagine, some manufacturers discovered that later on.