Response mode transactions in IMS

I've been evaluating Micro Focus Enterprise Developer, and I've run into another show-stopper for IMS/TM:

All of our IMS online transactions are defined as RESP(Y), which means:

The terminal from which the transaction is entered is held and prevents further input until a response is received.

What this does not mean is that a reponse-mode transaction has to return a response. It is OK to message switch to other transactions (even ones with RESP(Y) as long as at some point, you eventually do ISRT a message back to the terminal.

In fact, this sequence is allowed:

  1. User hits Enter on a screen A
  2. Tran A gets screen
  3. Tran A ISRTs via altpcb to tran B (a program-to-program message switch). Tran A is done.
  4. Tran B ISRTs via altpcb to tran C, D, E, and A again. Tran B is done.
  5. Tran C starts
  6. Tran D starts
  7. Tran E starts
  8. Tran A starts
  9. Tran C ends without inserting anything
  10. Tran A inserts screen back to terminal
  11. Tran D ends without inserting anything
  12. Tran E ends without inserting anything

even though all of the transactions are RESP(Y).

But in MFED this doesn't work. When tran C ends (step 9), MFED abends it with error

CASTM5052E IMS TM response mode transaction C terminated without a response

From what I can tell, it is requiring any transaction that was defined as RESP(Y) to return a response, even though that is not required.

(Note that one reason is that it is possible for the same transaction to be entered from a screen vs. PTP message switch.)

Is there some other setting in MFED I'm missing that would fix this?