On Line #66 of the conf/sip_profiles/external.xml file, the 3pcc global option is commented out by default. I don't know if this 3pcc is a fortunate or unfortunate option to have, but it will make WhistlePhone to work properly. Without the 3pcc option, there will be no incoming calls from WhistlePhone (FS CLI will dump some messages as shown below) unless FS registers to all WhistlePhone proxy servers as shown in here. The question I have is if it is safe to enable the 3pcc option. If it is, then I don't mind to go ahead to update the wiki page.
2011-10-01 16:24:23.328125 [INFO] sofia.c:5373 No SDP in INVITE and 3pcc not enabled, hanging up.
FreeSWITCH hosted on a Seagate DockStar with OpenWRT and ONLY consumes 3 Watts of electricity.