[dfx] use private key from crypto coprocessor as identity

I want to use a private key that cannot be saved as PEM in order to sign the message to be sent to a canister. Is there a way to do that in dfx? I know that one can use ‘dfx canister sign …’ to save a signed message.json file and then ‘dfx canister send … the file’.
I see no way to get the message I need to sign. If I could, I could sign it with a separate process and save it for sending. I would welcome any idea on how this could be done.


This will be supported soon (depending on your setup):