Can you use iManager on OES2 SP1 (iManager 2.7.3) to manage a 100% "pure" NetWare NCS 1.8 cluster?

If I try to click on cluster options and select the cluster, I get:

Error: Clustering Error
File Protocol error occurred: cannot open the NCS version file on the selected cluster. The Cluster software may still be running on this server.

But if I use iManager 2.7.3 on NetWare, it works fine.