Put the following script into a text object:
Sub Object_onscriptenter
object.SetTimer 1, 1000
End Sub
Sub object_ontimer1
t = FormatDateTime(time(),3)'---Get your system time
setclock = FormatDateTime(Dateadd("h",6,(t)),3)'---Add 6 hours to your system time
object.text = setclock
End Sub
The setclock line can be modified to however many hours ahead or behind you want to set the clock to. Simply change the 6 to +/- any number.
For example, 8 hours behind your system time would be: setclock = FormatDateTime(Dateadd("h",-8,(t)),3)
For further information check out these tutorials and articles:
SCRIPTING 101
SCRIPTING TIME
ANALOG CLOCK (where I got the snippet of code above)
VBSCRIPT DATE/TIME FUNCTIONS (such as FormatDateTime and Dateadd)