You can’t, not without making it chronically nose heavy. Use it in a mini quad and buy the 200mah Mini packs from Hobbyking instead. $2 isn’t that much of a steal, certainly not worth embedding an $80 plane in the turf over.
I fly my Sport Cub S with 500mah batteries all the time especially if it is windy. I kept the Micro 1.25 JST connector and soldered in a 2.0 JST connector so I can use either size battery. Made a new hatch on the bottom so I can slide the 500 mah battery in held on with a bit of Velcro.