Finally got my Subsonic working on my Diskstation Synology (NAS).
1. In Package Manager, add the "Java Manager" package and follow the instructions for downloading (I used jdk-7u80-linux-i586.gz), then uploading java to the Java Manager.
2. In Package Manager, add "Tomcat7" package.
3. Download and use WinSCP, login as root and use your admin Diskstation password. Navigate to "/volume1/@appstore/Tomcat7/src/conf/tomcat-users.xml". Edit this file: <tomcat-users> section, add the following before the last </tomcat-users>:
<role rolename="admin"/><role rolename="admin-gui"/><role rolename="manager"/><role rolename="manager-gui"/><role rolename="manager-script"/><role rolename="manager-jmx"/><role rolename="manager-status"/><user username="user" password="password" roles="manager-gui,manager-script,manager-jmx,manager-status,manager,admin,admin-gui"/>
Be sure to change "user" & "password" to whatever you like. This is what you'll use to login to the Manager App in Tomcat
4.Create a folder at /var/subsonic (and I gave it 0777 permission). Using the Command window in WinSCP type without the quotes: "mkdir /var/subsonic". Then to set permissions type:
chmod 0777 /var/subsonic
5. To enable transcoding, point subsonic to synology's ffmpeg instance by running the following line, using the command window in WinSCP:
ln -s /usr/syno/bin/ffmpeg /var/subsonic/transcode/ffmpeg
6. Stop, then start tomcat again (it has to be restarted so that it can load the updated tomcat-users.xml file.
7. Now you can go to your Tomcat instance (defaults to port 7070) and click on app manager, or just go here: http://SYNOLOGY_IP:7070/manager/html and look for the "Deploy" section. In the subsection called "WAR file to deploy" upload the subsonic WAR file. Then hit deploy. It should either automatically start, or you may have to click the "start" button next to the subsonic entry in the list of your tomcat applications.
8. That should be it! http://SYNOLOGY_IP:7070/subsonic should load up.
9. In order to get subsonic to read my music folders, in the diskstation create a user "Everyone" and allow read access to them (e.g. set "Everyone" with read access to /volume/media/music/rock).
10. In Subsonic create a user called Everyone. Log out as admin and log back in as Everyone.
All should be good!