AR invoice and Sales order # to be the same

Question

this is an email from one of our customers, and we cannot confirm if it is possible. Can someone help?
We require the AR Invoice # to be the same as the Sales Order Invoice #, so that the Account Statement shows information (the original Sales Order #) that the client understands. If the Account Statement were a little more flexible, we might be able to get around this issue, but it is hard to change the SAP account statement.
Currently we manually copy the S/O # over from Every Sales Order as we copy the S/O to A/R. This is inefficient & should not be necessary.
Plus, we want to automatically copy one of the dates over from the S/O. Surely other businesses want to copy over a S/O date to the AR Invoice (for instance, to fill in the Document Date field of the AR invoice - ie. the document date of the S/O).
The Bug in SAP is that you can not AUTOMATICALLY retrieve the SO# (using a Formatted Search) BEFORE saving the AR Invoice.
This whole issue also applies to copying over POs to A/P Invoices.
(AFTER saving the AR Invoice on the database, my formatted search CAN pick up the original SO#, but by then it is too late, because the AR Invc # has to be Specified BEFORE saving the AR Invc)

Answer 1

Dear Mr. Emery,
I hope you don't mind if I am interfering in your issue.
Regarding the manual Invoice number to be equal to the original based Sales order Number AND
providing that you only work in a 1-2-1 relation between the two sales document:
Settings:
Create the following query: SELECT $[$38.44]
Link that query to the invoice number field, refreshed automatically on 'series, Displayed Saved-User defined values
Process:
     The user opens a new sales invoice
     The user choose the Business Partner
     The user choose u2018copy from a sales orderu2019
     The user change the series from u2018primaryu2019 to u2018manualu2019 -> this trigger the query
Regarding the invoice posting date = based sales order posting date:
     Settings:
          Create the following query: SELECT CONVERT(CHAR,T0.DocDate,103)  FROM ORDR T0 WHERE T0.DocNum =  $[$8.0.0]
          Link that query to the invoice posting date field, refreshed on u2018Seriesu2019, Displayed Saved-User defined values
     Process:
          When the user change the series to manual, the based sales orderu2019s posting date will automatically overwrite the invoice posting date.
This solution does not cater for an invoice created directly (Not based on Sales Order). But you have here a basic idea on how to solve your issue, thus easily can improve the solution.
Tested on 2007A PL42.
Regards,
Frederic Bada
Pretoria, South Africa