There are several different mechanisms used to create logfiles on SME:
- syslog
- multilog (for most of the supervised sme services)
- other (apache logs, for example).
I think you'll have quite a bit of difficulty sending all logs to another host.
One option that occurs to me (which may not work at all, and may break your SME server for all I know) would be to make /var/log a mount to an nfs share on your synology...
I don't suppose you'd be willing to simply rsync your logs to the synology every 15 minutes or so?
Is there a specific log file you want to store on the synology?
Are you concerned about log file security (eg intruders retroactively editing log files to conceal activity), retention (the amount of time included in historical log information), or disk space on the SME?