To get our networking going, we need ifconfig route etc. Maybe you included it in busybox, if you didn't (like me), you need the net-tools.
The net-tools can be found at Freashmeat and is currently at version 1.60.
After untarring i just typed make in the new directory. This comes with a few questions for supported interfaces and protocols. Be sure to include what you want. For me IPv6 and sit tunnel where special.
The compiled programs are quite big, stripping off debug info helps a lot. Copy these files to your /sbin directory of the ramdisk image, and see if whe can configure networking.
You can test your network functionality by configuring your device and try to ping it from an other machine.
You can use ifconfig [interface] [Address] netmask [netmask] to configure the interface (usually eth0).
You can ignore any errors of route and ifconfig about the /proc filesystem not mounted.