The 'config' commands in emptool work well:

./emptool empeg-car
2000 Checking connection                                                 [Done]
2121 Downloading
2121 Starting download                                                   [Done]
2122 Retrieving tags index                                               [Done]
2123 Retrieving databases                                                [Done]
2124 Retrieving playlists                                                [Done]
/> config
2124 Retrieving playlists                                                [Done]
[menu]
quit=1
[network]
dhcp=0
ipaddress=192.168.2.3
netmask=255.255.255.252