When sending a SwiftNet delivery notification, if the initial try failed, there is no retry to send it.

This happened if the "Ack option" in the trading partner configuration is setted to "By monitor".
To change this behavior:

-- set the "ack option" to "By User"

-- create a model which will be use to send the delivery notification :
type=Receipt
receipt reply to xfer=&(local_ident)
retry count max=2  <------ Number of retry for the delivery notification

-- create a decision which will be selected when an incoming SwiftNet transfer goes to To_Ack state, and which will call the previous model as action:
protocole=SWIFTNET
direction=I
state=W