Charges User Hook Create_Charge_Details_Pre

All,

We have a requirement to set the Bill to/Ship to on charges to values different from the Service request or IB Owner.  I would like to do this by using the Charges User Hooks.  Specifically I hope the Create_Charge_Details_Pre hook to set the values for the Bill to & Ship to as the line is created,  I am having difficulty finding any specific documentation about how to us this hook or even examples of code where it is used.  Has anyone used this hook in the past?  Could you provide some details on how to use it to set values