save configset with Simulink.SaveVars in Matalb2015b

In my workspace there are variables and also configsets. When I do Simulink.saveVars('xx.m'), the other version of matlab will save the configset parameters in the m file. But Matlab2015b does not do it, so when I clear the workspace and load the m file, the configset in the workspace is complete different. How can I solve this problem in Matlab2015b? Thanks!