Create a throw skill in your database. Put the notetag in the class you want to have the throw command:
<Battle Commands>
Skill:ID <- Put here the ID of the Skill
</Battle Commands>
You also need to add the Attack, Guard, Items and normal skills command to the notetag, otherwise they won't show up.
<Battle Commands>
Attack
Guard
Skill:ID <- Put here the ID of the Skill
Skills
Items
</Battle Commands>
Then it should look something like this.