Well, you can do this in NearInfinity too, in fact if you use the newest version, it will have all the Exclusion flags, (0-14) that you need, identified.
Anyways it doesn't matter which editor you use.
But at
DLTCEP, the next thing you do is well go back... all the way to the start screen, in where you click the Setting button, and uncheck the Read Only -tag.

Then you go back to the Edit-> Spells -> Load Spell, and pick up the wall of fire... and you'll see the "General properties" tab, in which has the "School exclusion" and under it should be
"0x0000-Unused" or something like that, to edit that you just switch that to
"0x0004-Exlude Good" to make it not appear for good cleric&priests ... or you can actually exclude it from all clerics and priests, paladins and rangers if you want, by manually editing the number to "0x003f-*" , in which the * doesn't actually matter, as only the numbers matters. Then you save the spell etc...
Edited by The Imp, 05 April 2013 - 05:11 AM.
Yep, Jarno Mikkola. my Mega Mod FAQ. Use of the BWS, and how to use it(scroll down that post a bit).
OK, desert dweller, welcome to the sanity, you are free to search for the limit, it's out there, we drew it in the sand. Ouh, actually it was still snow then.. but anyways.