1. You cannot use the inverter in an environment where it is exposed to oil mist. 　
You need to enclose the inverter in an enclosure and then install the enclosure in the environment.
(You need to take a sufficient countermeasure against temperature raise.)
You also need to purge air.
(Pump clean air from outside to make the in-enclosure air pressure higher than the outside air pressure.)
2. Even if you use the panel through attachment, the heat sink and cooling fan are placed in oil mist and it does not work against oil mist.
I can still provide you with the outline dimension drawing of the attachment, but it will not work as a countermeasure against oil mist.
Contact us to obtain this attachment installation diagram.