activate dialog option depending on condition?

[deltree]

hi again,
I've got a problem with dialog scripting:
I'd like to enable some dialog option (in the dialog screen) depending on wether the character has an object or not.
For example, the player has a stone in is inventory, and when he talks to another character, the dialog option:
"what can you tell me about this stone" will appear ONLY if the player possess the stone.

[Pumaman]

The easiest way is to use SetDialogOption to enable it when the player picks up the stone.

[deltree]

thanx!