This is my problem with IPMI in tyan 8230 motherboard:
In the BIOS, I set the ip configuration to STATIC. I have to provide only an IP address and a subnet mask. After saving the configuration, the gateway doesn't automatically updated. Please see the reference manual at http://www.tyan.com/manuals/S8230_UG_v1.02.pdf pages 57-58
After reseting the system, I can only ping the ip address from the local lan.
I'm not sure what you're trying to do and The PDF is loading really slow for me, but isn't that the IPMI lan setup which usually only works over the local lan. The network setup for the OS is done in the OS.