No logs from Fortigate 80C

Hi.

I've just taken over a network with two 80C's in HA - v.5.6.3 build 1547 (GA).

Last week I opened up a port for a supplier but found that I was not able to troubleshoot because there were no traffic logs, none! The boxes are set up to log to memory, I can send to a syslog server, though, but that plays merry hell with formatting. Local traffic log is set to ALL - both in the GUI and from the CLI.

I've never worked with Fortigate before, but have set up and maintained a few competitors, so I at least imagine I know how this should work.

Settings are 

Local log to memory - On

Send logs to syslog - On

IP address/FQDN - <IP>

Event logging - all off (for test purposes)

Local traffic log - all on (ditto)

GUI preferences is to display logs from memory

Is there a way to get this logging to work or should I just drop the whole issue? (And replace the devices...)

Regards

Kjetil Thorstensen