Hello
After struggling to find a way to change transmission password because the default one is empty I found the way to change that password...
My box is a Buffalo LS 520D with firmware 4.50
First, we have to enable ssh to get root access witch is very simple using acp commander witch all of you are familiar with
java -jar acp_commander.jar -t yournasiphere -ip yournasiphere -c "/etc/init.d/ssh.bak start"
The root password is empty but in case it isn't just use this command to change the root password to something you want
java -jar acp_commander.jar -t NAS_IP -ip NAS_IP -pw Youradminpassword -c "(echo newrootpass;echo newrootpass)|passwd"
You have to change settings.json permission
java -jar acp_commander.jar -t yournasiphere -ip yournasiphere -c "chmod 777 /etc/transmission-daemon/settings.json"
Third, you have to use WinSCP windows program and login through sftp with your ssh credentials and navigate to:
/etc/transmission-daemon/settings.json
After, write the rpc-password in the /etc/transmission-daemon/settings.json file, in double-quotes
At the end connect through putty with ssh details and run this command
/etc/init.d/transmission-daemon reload
Voila your trasmission password was changed successfully