pre-FP2007:
Because the Enhanced Write Filter must be enabled, there is no way for the XPE OS to determine whether it has already adjusted the system clock for daylight savings. This means that during daylight savings, the OS will reset the clock on every reboot of the cabinet. This is undesirable behavior. To remove this feature, you must add two new registry keys to image and disable one key from the NLS: Time Zones component. The registry keys to be added are determined through the use of regmon on any computer. Simply change the system clock to not adjust for daylight savings and see what registry keys are added/modified.
In our case (maybe everyone's?), two values must be added in the HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation key (in Extra Registry Data):
DaylightBias (REG_DWORD) = 0
DisableAutoDaylightTimeSet (REF_DWORD) = 1
In the NLS:Time Zones component, disable this value in the HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation key (near the bottom of a very long list):
DaylightBias = -60