OK thanks Archie for saving me a lot of testing trying to get that working. I guess the workaround (for now)is to read and copy the data from the DH+ SLC to the CLX PLC first, then read the CLX version from AHMI.
We have multiple DH+ networks set up like this with the majority of our plant's data behind these DH-RIO interfaces- if you ever get the time to add this feature, it would be a great one!