AB 1738-AENTR to Omron PLC eip communication

I am trying to communicate to a AB 1738-AENTR on a OMRON ethernet/ip network. I have configured the AENTR module through the web browser and have been using Omron's Network Configuration tool to set up the network. I
can see the AENTR but cant seem to communicate to it. I think this has something to do with the input and output byte size? Does anyone out there have any experience in setting up a 1738-AENTR in a OMRON system? If so, how do I determine what the proper byte size is? Also, is there something else I should be doing to get the module working?

Sorry I don't have any advice but that would be a fairly unusual arrangement around here.