The closest you can get is to enable "Accounting" in the Track field along with "Log" to get this information. Every 10 minutes or when the connection ends (whichever comes first), additional information is added to the log entry including firewall egress interface, connection time, and bytes/sent and received. If these values are nonzero two-way connectivity is working.
Modifying the state of SecureXL won't change this, but if you want to use fw monitor to capture accelerated traffic in R80.20+ check out the -F 0,0,0,0,0 filtering syntax for fw monitor.
Updated 2023 IPS/AV/ABOT R81.20 Course now
available at maxpowerfirewalls.com