Return new doc num from std R/3 to custom program?

Question

Colleagues,
I am designing a process in FI, and need some help with a technical problem.  I have a custom table that contains a list of items, each with a status code.  This list is presented to the user in a screen.  Each line on the screen has a "Take Action" button.  Depending on the item status, "Take Action" will transfer control to a different FI transaction -- F-28 (post with clearing), or FB01 (create document).  I want to capture the results of the standard transactions (the new document numbers) back into the custom table. 
Is this possible?  Both standard transactions will display the new document number in the status bar, but how do I make that information available to the custom program? 
My plan is to have the standard transactions open in a new session (window), so that user can switch back and forth between the custom transaction and the  standard transaction.  However, I cannot trust the user to capture the document number manually.  I don't think a user exit would work, because there is nothing to distinguish these transactions from the hundreds of thousands of other F-28 and FB01 transactions.
In my research, I did find a reference to a function module FI_MESSAGE_GET, but I cannot find any information about it, and the code itself is not enlightening.
Thanks in advance for your help
Patricia

Answer 1

Hi All,
Thank you for your suggestions. I am running them past my developers and will get back to you when I have heard from them.
The reason for the custom transaction is this: External partners are transmitting data.  We have a batch process to automatically post this data.  Unfortunately, the partners do not always send enough data for the batch process to figure out what to do.  In our new process, we will capture the failed transactions in a log file.  We will present the logfile data to the users in a nice simple screen (like a spreadsheet) that allows them to click through to the standard posting transactions.  They need to have both sessions open so that they can figure out how to do the posting, based on the data in the log file.
Because of the user interaction that is required (and the nature of the specific users who will be interacting), we cannot use BDC sessions -- we have to launch the standard transactions (such as FB01).
All of this is pretty easy -- the tricky part is getting the actual posting data back to the log file.
Thanks again!
Patricia