Okay, it seems the BIOS way is the only possible for me since the OMSA does not show me the virtual disks.
The VIB was installed following the guide and is installed as you can see in the output of
esxcli software vib list
OMSA web connected the esx host above shows me the following menu entries:
I think the virtual disks should show up below "Speichermedien" but it says it cannot find any controller although the PERC is installed in PCI slot # 8 which i can see under the "Steckplätze" (slots) menu.
Thanks anyway for your great assistance!