5th Door lock catch broken
 

Good day, I have a 2010 PajeroSport and the plastic catch in the locking mechanism of the 5th door (Luggage Compartment) broke off. Is it possible to only buy and replace this catch or does the whole locking mechanism need to be replaced. Where can I obtain a part number if it is available. The white portion in the middel of the attached photo has a catch that moves the steel lever to open the locking mechanism and then the door opens.
https://cimg1.ibsrv.net/gimg/mitsubi...45a8873396.jpg


If this part is available, how can I replace it myself?