Version 3 IRLP boards are supplied with three N/O MOSFET switches capable of sinking about 2 amps.  The following script, when placed in the /home/irlp/custom/custom_decode file, will allow ON/OFF control of these AUX switches.  Again, these are only found on version 3 boards.

# The following code is a sample of turning ON and OFF AUX1 contacts
# These lines need to be placed within the custom_decode file
if [ "$1" = "123" ] ; then "$BIN"/aux1on ; exit 1 ; fi
if [ "$1" = "321" ] ; then "$BIN"/aux1off ; exit 1 ; fi

#123 turns on the AUX1 N/O contact and 321 turns it off.

See the Custom Decode help file located here