Is it possible to hand solder a component with a peak temp of 250 C?
60/40 solder melts at somewhere around 180 to 190 degrees Celsius, not 300-something.

Use a temperature-controlled soldering station.

In any case, the temperature in the device itself is not necessarily as high as it is at the joint being soldered. If you work quickly, you can create a fast, local temperature rise at the joint.

Also, depending on the size and geometry of the part being soldered, sometimes it is feasible to introduce a sink which removes heat somewhere along the pin between the joint and the part itself.