Mirko, SXP has a different plug. I can't remember the specs but the centre pin is thinner. I think this is what you need from Jaycar.
https://www.jaycar.com.au/2-1mm-dc-p...ector/p/PP0510
https://www.jaycar.com.au/2-1mm-inli...ector/p/PS0526
Don't forget to check the polarity when you wire it up! Also worth double checking the barrel length is the same.