Question about spell effindex

[sjizzle]

http://getmangos.eu/wiki/Gossip_menu_option

On the bottom of this page I saw this:

CONDITION_AURA = 1, // spell_id effindex

Can anyone tell me how to find and where to find effindex of a spell?

[Schmoozerd]

SpellWork or (in this case) wowhead can be enough.

the effect index is the index of the effect responsible for the effect you want to check - the aura here.

so a spell that

0) does some damage

1) applies an aura

2) has some dummy effect

would have "1" as effect index for the aura

[sjizzle]

I want to create a gossip menu where you can ONLY select options if you do have the following buff:

http://www.wowhead.com/spell=13326

So if you have the buff, you can talk or select the gossip options. How do I use the effectindex in this example?

( based on http://getmangos.eu/wiki/Gossip_menu_option )

cond_1 = 1

cond_1_val_1 = ??

cond_1_val_2 = ??