If I add this:
<parameter key="module_shop" value="1"/>
<parameter key="shop_buyable" value="bow,2456,350;crossbow,2455,450;
or this:
shopModule:addBuyableItem({'bow'}, 2456, 350, 'bow')
shopModule:addBuyableItem({'crossbow'}, 2455, 450, 'crossbow')
The npc can not see a difference...