Hey,
If I remember correctly also, IBMs implementation of iSCSI in AIX is very ... fundamental. Meaning, they don't have instructions available to support the entire protocol stack. Last time I dealt with this question, the implementation had a scale-out storage architecture similar to vsan in many ways. There would be a single IP for the cluster to represent storage connectivity operations, with iSCSI commands leveraged to tell endpoints which nodes to connect to for preferred vs secondary data, alert for data movement, etc. AIX did not fully support the iSCSI redirects required to make this all work, and IBM had no intention of updating the stack (at the time). This was about 3 years ago, so may have changed!