In 5.16 I was able to edit the amount of charges in a wand, by right-clicking on the item in the equipment screen. In 5.17 there is no way to change it.
This should be a bug, still occurs in 5.17.16. Definitely need this!
Note: in previous versions of PCGen there was a bug wands with changed charges. Sometimes on reloading a saved character with such a wand, a second fully-loaded wand was created in the inventory.
The new Modify Charges menu added in may have fixed this issue. Could you confirm please Stefan, Dave or Jonathan?
Downloaded ver5.17.17, release 10 September, 2012. The menu option appears when you right-click on the wand under the purchase tab. I did notice that if the wand is the only solitary item purchased, you change the amount of charges, then switch to the Equipment tab, the new amount of charges is not updated to the item. This doesn't happen if you have more purchased items. Must be some sort of refresh glitch.
Remains an issue in 6.06.01
The Modify Charges menu is needed in the equipment tab also.
In order to reduce the number of charges on a purchased item (a very common task), you have to sell the item then repurchase the same item and edit the charge number before re-equipping it. This is a real pain.