need to send back diff msg type back to the sending thread

I have a scenario in which we are testing some changes with a new orders bi-directional interface.  The sending thread sends a reflex test (ORM msg with SN order control code for the new reflex test).  It expects an order acknowledgment back from the receiving thread – msg type ORM order control code of NA.  Even though it knows the order# that this reflex test is being added to, it needs to have that order acknowledgment msg befor the reflex test can be resulted.

I have thought of a couple of options.  

#1 Create addtl thread that I send a raw copy of the ORM msg with the reflex test, chg the order control to NA (from SN), chg source/receiving in the MSH and send back to the sending thread.

#2 Use tcl proc, copy the reflex ORM (SN) msg and change it to NA msg and send it back to the sending thread.

Which is the best option.  #1 sounds seems the simplest, but I am concerned about delays since the lab techs add the reflex test in the LIS sending system and then turn around and result it as the order acknowledment msg usually comes back instantaneously.  #1 might cause delays.

I appreciate suggestions on the best way to go.  I am still working on the receiving system to send back the order acknowledgement but due to time constraints may need to put something into place temporarily.

thanks,

Nancy