By Wayne Brill
Here is a VB example that changes the Quantity of a BOM Row. To test this code you can add a button to this SDK sample:
C:\Program Files (x86)\Autodesk\Autodesk Vault 2016 SDK\vs12\VB\ItemEditor
After the code runs you can see the Quantity being changed in Vault Explorer. The ItemBOM and ItemAssoc are retrieved from the Item being edited.