albatroz
v6.x should do everything that v5.6 does and better.
Just guessing but your mail problem may be related to this, from v6.0 releae notes.
A transparent SMTP proxy has been added, to force all outgoing SMTP connections to go through the SME server. This feature enhances security with respect to viruses and worms that use SMTP to propagate themselves.
If you wish to disable this proxy, you can do so via:
/sbin/e-smith/config setprop smtpfront-qmail Proxy disabled
/sbin/e-smith/signal-event remoteaccess-update