Mounting Opti level sensors

[almost]

Hi,
I just received my 2 opti level sensors among with the 2 PL-PF Bases I orderd.
Well, I can't find the way to mount the sensors, as opti sensors needs to be mounted horizontally.
Am I doing something wrong, should I order anything else?
Thanks.

[Matthias]

you also need matching adaptor, the article "PL-S12 angled"

[almost]

I order them,
Thanks Mattias.