Adding Edges that add to damage die of unarmed attacks
 

I added an edge Martial Arts, that does d4+str damage using the following Evaluation script.
perform hero.child[wpUnarmed].setfocus
focus.field[livename].text = "Martial Arts"
perform focus.assign[WeaponDie.2]

Phase is set to initialization with timing of 1000 everything works greaqt unarmed is replaced with martial arts and it shows the correct damage, however when I add the edge Advanced martial arts I use the same eval code as above, but change weapondie to 3. After adding the new edge the damage still shows up as only d4. How can I make the damage go up with each additional edge?