xs++ doesn't like the w550/w600, it's worse in older versions.
to upload a custpack with setool2 lite, you need to create a folder called tpa then inside that folder a folder called preset then inside that folder a folder called custom, so it goes tpa/preset/custom with the custpack in the custom folder. and zip it up, then extract it to check it some zip programmes will mess up the structure, the put the tpa.zip (MUST be .zip & not .rar or anything) in the MISC box in setool2 lite and then press flash.