Well, it takes Access or Munin.
The basic table structure is info Wonderous Item and info Wonderous Item Bonus (or substitute Wonderous Item for Rod or Ring or Armor or Weapon, you get the idea)
You can use eTools house rules to enter the item, to get it to effect stats, you then use Access or another 3rd party software like Munin. Open the corresponding Bonus table. You then select the item, type of bonus (enhancement, resistance, etc), the amount, the skill or stat it effects. Add a line for each type of bonus the item adds.
I hope that the house rules or Davin's ET Helper one day will allow us to add these items without Access or Munin.