Update Contract Invoice header with Custom Field on Contract

[Jozef Pietruniak]

I'm writing a smart event that will populate the Customer PO field <SODOCUMENT.CUSTOMERPONUMBER> on a Contract Invoice with the value from a custom field {!SODOCUMENT.CONTRACT.CUSTOMER_PO!} on a contract while generating the invoice.

My API reads as follows:

<update_sotransaction key="{!SODOCUMENT.DOCNO!}">
<SODOCUMENT.CUSTOMERPONUMBER>{!SODOCUMENT.CONTRACT.CUSTOMER_PO!}</SODOCUMENT.CUSTOMERPONUMBER>
</update_sotransaction>