How to fix pugeot 406 key fob broken micro switch?

The micro switch under the round button on the key of my Puegot 406 has lost its top half can I solder a new one on. If so where can I get one.The button cell is 3 volts,is the switch 3V? The switch is 6mm long and 3.5mm wide (approx )silver on top black below and has two visible terminals.Does anyone know if this switch has a name or number.