wincc flexible trend x axis time set

Dear all
I am using wincc 2007 to log the data.
My client wants to see the historical data so that i have configured the trend view to show log value.Also on x axis there is external time tag to enter the time and it is working fine.
But client wants to adjust the start time and end time of the x axis so that he can see the trend in perticular time zone that he decided

How can i adjust start time and end time of trend view x axis in winccflex runtime??
My PLC is S7 300
Warm Regards
Nehe

Wating

Hii all
Wating solution for the problem
Nehe