INFSmartFoxUser and storing additional information

[arnieterm]

For an iphone application I would like to store additional information of a user like say his/her display name so that when a request is sent by a user let say for sending invitation to play game then this custom information will be helpful. Do I need to use "setVariables" method of INFSmartFoxUser?
Also each response of type onXXX like onJoinRoom, etc do contains sender user information also?
Thanks
Arnieterm