syslog over tcp and define management IP as source

Hi,
I did the following as described above:

# modify /sys syslog include "destination remote-server {tcp(192.168.10.26 port (514));};"

Checking the configuration:

# list /sys syslog

sys syslog {

include "destination remote-server {tcp(192.168.10.26 port (514));};"

}

I added and deleted the following:

Added the configuration above (GUI), list /sys syslog shows:

# list /sys syslog

sys syslog {

include "destination remote-server {tcp(192.168.10.26 port (514));};"

remote-servers {

remotesyslog1 {

host 192.168.10.26

}

}

}

Adding Remote Syslog Server with GUI sends UDP packets.

Removing it, no packets are send to the syslog-server.

This was seen with tcpdump on the F5 and the firewall between the F5 Big IP and the syslog-server.

What do I missing, to make it working?

Thanks in advance
Christian