Is it possible to let the ASA 5505 write it's syslog messages to a syslog server on the central network where the ASA 5550 is? (over the ipsec tunnel?)
I tried this. The tunnel is up but I get the message Routing failed to locate next hop for udp from NP (ASA 5505 ip) to inside: (syslog server ip).
I would like to suggest that you configure the inside interface as the management-access interface. Include the inside interface IP and syslog server IP address on the NAT 0 ACL and crypto ACLS.
You can checkout the "management-access" when you want to managed an ASA on its inside interface through the VPN 7.2 command referrence below:
I am currently running the VPN configuration on 8.2 and SNMP polling is working.
Hope this helps.