You have used change class option, to change battleset, yes? The way I'd get around it is just create a character for each different piece of armour etc, then whenever he changes armour, keep your common event code the same, but instead of change class, take Taz Armour 1 out of your party, and replace him with Taz armour 2, and when in, you can change his name from Taz ARnour 2 to just Taz, using the change hero name tab on the event menu: 1st page, 2nd column, 7th down. So hopefully your code should look like:

<>branch if taz leather armor equip
<>Change party members: Taz cloth armour remove
<>Change party member: Taz leather armour add
<>Change hero name: Taz leather armour's Name Taz

If I get the time, and it still doesn't work, or you don't get a word I've said, then I will post a pic for you.