Change one-time customer name in SO after billing

Hi,

We are using one-time customer and created sales order and billing document and FI document is also created, now if the name of the one-time customer is changed in FI document (FB02) then it is automatically changed in SD documents also i.e Sales Order, Billing document etc whereas if the one-cusomter name is changed in the Sales order (VA02) then it is not updated in the FI document.

I would like to know why this is so, is this the standard set-up i.e change of one-customer name in SO not update in FI document.

Has anyone come across this sort of issue, if yes, how to resolve it.

Tks,

VS