Enabling ARP / RARP Using NETOS 5.0

I currently using the NET+50 Chip and NET+OS 5.0 from Digi. I need to announce my product at power up and was told that the ARP protocal was the way to do this. It looks like NetOS 5.0 has support for the ARP protocal ( at least I find .h files for ARP) but I see no way to enable this feature. Has anyone been successful turning on the ARP feature and if so how have you done it?