Loading textures from cocostudio json

I made some ui widgets by cocostudio.
And for some reason, i want to move texture images to another directory.
So, I add search path FileUtils::getInstance()->addSearchPath("some/other/directory");.
But when loading widgets from json,
GUIReader seems not to use added search path above.
How can I solve this problem?

I’m using cocos2d-x 3.0 beta2 from github develop branch with latest commit.