Synology has really outdone themselves with DSM 4.0:
Although this is the first beta, it introduces a number of improvements with the most noticeable a completely revamped user interface which includes widgets and vast UI improvements over the desktop-style dashboard in DSM 3.0:
The system information is now displayed in a side-widget and several widgets (such as the Package Manager) have received a complete rework and now include features south as Synology Cloud Services for seamless syncing between devices (no support for OS X yet) and Antivirus Essential which runs antivirus scans on your Synology NAS.
My installation and customizations (such as Squid Proxy server) initially did not work, since this beta resets IPKG Optware. The fix is relatively simple and works after a reboot:
1) edit /etc/rc.local and add the bold line:
#!/bin/sh
mount -o bind /volume1/@optware /opt
# Optware setup
[ -x /etc/rc.optware ] && /etc/rc.optware start
exit 0
2) edit /root/.profile and adjust the bolded path:
PATH=/opt/bin:/opt/sbin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/syno/sbin:…..
Reboot your Synology and IPKG and other services residing in /opt should now work again.