Taxation form, Hungary

Hey folks,

I would like to fill out a taxation form. 

I am from Hungary and I am working in a form that called KATA. (I have a full-time job and besides that I am a self-employed as well).

I assume that I need to fill the W8-BEN doc, but I don't know what should I write here:
"Special rates and conditions (if applicable—see instructions): The beneficial owner is claiming the provisions of Article and paragraph ...A.... of the treaty identified on line 9 above to claim a ...B.... % rate or withholding on (specify type of income):.....C..
Explain the additional conditions in the Article and paragraph the beneficial owner meets to be eligible for the rate of withholding: ...D.."
So, I don't know what should I write for A, B, C, D. 

Another question is that I have an EU taxation number. Is it the requested number in the so-called "foreign tax identifying number" field? 

Huge thanks in advance to everyone, who will try to help.

Moni