It appears as though yo may have run out of options thus far.
Have you thought outside of the box? Can you add a shunt trip to the exisitng breakers of install one that does?
Then use an external GF relay that would trip the ST.
As and example this is a typical D64 relay:
Ground Fault Trip Current Level 30 mA ? 6.0 Amps in 8 settings: 30mA, 120mA, 210mA,
300mA, 600mA, 2.4Amps, 4.2Amps, and 6.0Amps
http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/tb04900002e.pdf
Ground Fault Relays and Monitors:
Type D64 Series?Digital Ground Fault Relay System : 32.2-1
EGF Series Ground Fault Sensors: 32.2-8
Have you thought outside of the box? Can you add a shunt trip to the exisitng breakers of install one that does?
Then use an external GF relay that would trip the ST.
As and example this is a typical D64 relay:
Ground Fault Trip Current Level 30 mA ? 6.0 Amps in 8 settings: 30mA, 120mA, 210mA,
300mA, 600mA, 2.4Amps, 4.2Amps, and 6.0Amps
http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/tb04900002e.pdf
Ground Fault Relays and Monitors:
Type D64 Series?Digital Ground Fault Relay System : 32.2-1
EGF Series Ground Fault Sensors: 32.2-8