Welcome to the forum, ONO.
I held back posting on this because I have not sharpened any planer blades. I contacted support in Sweden. Our support team is presently attending a trade fair in Germany, so I will post. The standard method is to use the leather honing wheel, just like other blades. Due to the length of the blades, this is done hand held. Working carefully, you should have no problem.
I recently tested 80 and 180 grit grinding wheels. Going directly from the wheel to the leather honing wheel, I was amazed with the difference in sharpness.
Keep posting!
Ken