I soldered on a sheet of copper covered solder with a walnut husk under it to act as a light spring
If you touch it quick with lead solder it will stick to the nickle plating but it won't burn the plastic.
Tin both surfaces and flux before you solder the new part on. Maybe I just did a press fit But I think it solders, was a few years ago.
Shitty design choice on Flukes part, that tab breaking is a COMMON problem I have seen many times on this forum.