Sorry for the late but it may help some people in the future.
If you want configure JAMES to send mails to external network you must edit the file conf.xml in the ${JAMES_DIR}/apps/james/SAR-INF.
Uncommented these line to define an SMTP relay server if necessary through the gateway:
<processor name="transport">
<mailet match="All" class="RemoteDelivery">
...
<gateway> smtp.gmail.com </gateway>
<gatewayPort>25</gatewayPort>
</mailet>
</processor>
Example to use the gmail relay server:
- POP Server: pop.gmail.com (on activation of the POP option of GMail)
- SMTP Server: smtp.gmail.com
- IMAP Server: imap.gmail.com
EDIT: gmail requires an authentication so you must set the gatewayusername and the gatewayPassword markups:
<gatewayusername>login</gatewayusername>
<gatewayPassword>pass</gatewayPassword>
See http://mail.google.com/support/bin/answer.py?answer=10350