You cannot use the AT10 for this. Your other option is a CANBUS-USB programming tool (which is what the ST10 is). Simrad
lists two others as compatible, one is the Kvaser Leaf and I don't remember what the other is. They are very expensive compared to the ST10 - I don't understand why Navico
would discontinue the ST10.
Short of that, the only ways I know are to use a Navico MFD (even a friend's), find someone with a ST10 to borrow, take it to a Navico dealer or send it to Navico.
Contact Navico and see what they say about the ST10 availability - maybe they have one laying around they would sell you. The ST10 uses simnet connectors and since Navico has gone completely to micro-C connectors, I suspect they are letting these other connector devices die. But they really should come up with another option.