I yesterday added
HEM (2nd edition) Model: DSB28_ZWEU, 3Phase4 60Amps
, and for this also only 1. clamp is visible. Probably Athom did not included 3.clamp version in their Aeotec app.
It would be nice, if they add support for this also (It worked for me in Fibaro system, but now I moved to Athom universe )