Multiple virtual Eth configuration (eth0:0, eth0:1)

Im trying to understand if it is possible to enable “virtual” eth interfaces like (eth0:0, eth0:1, eth0:2, etc) to aquire DHCP addresses from the DHCP server. (or use static assigned addresses)
I’ve read the api documentation and it says that it can be up to 4 virtual eth interfaces enabled but doesn’t say how to turn them on.
Im using Digi ConnectME dev kit with Net+OS 7.5
If anyone has an example on how to do this, i would really appriciate this.
Please help