its pretty easy - you'll need cheatengine to do it and here is how it works:
search for the id of your arcane explosion (ill use wowhead.com to explain)
Arcane Explosion - Spell - World of Warcraft
thats the page for Arcane Explosion Rank 8 the numbers behind spell= is the id
which means your spell id for arcane explosion is 27082
search that number
get all the black ids (NOT THE GREEN ONES ON THE TOP!) down into your list (just mark them alle, unmark the green ones and press on that red arrow on the right bottom side of the ids-found-box)
now you will need to replace it with a TALENT that you skilled (i used Arcane Focus Rank 1 - if you skilled to 5 you can use any from 1 to 5)
Arcane Focus - Spell - World of Warcraft <--- id: 11222
now freeze all adresses and change the value to 11222 (just mark all, right click, change record, value and enter 11222)
done!
cheattables are attached...
tested on MaNGOS rev 6005, 6167
credits goes to wrigle from ds
NOTE: If you got WoW Errors/Crashes use the FIXED Tables. Thx.