3rd Party Invoice reference SD-FI

SD Experts,

We are currently creating all invoices with an external application, we will be bringing the information into SAP after the fact in SD by creating a sales order, delivery, goods issue, etc. I would like to use a reference field to enter the invoice # from the 3 party billing, that can copy to the delivery, goods issue, and ultimately to the A/R Finance for easy reconciliation.

Is there a way that I can do this? I have tested the reference field in sales order but field does not carry to FI. any suggestions will be greatly appreciated.