This seems to set a default timezone/language but the timezone/language page is still displayed to the user for selection. I need to bypass this page i.e provide login name/password> click submit then go straight into Service Pages.
I have done this for one of my customer. The SD 4.5 SP is divided into number of frames. Please do let me know if you have solved this problem and please tell how you want your SP to change. I will send my whole code if you want the same.