By default, Windows uses Pacific Standard Time during setup unless another timezone is specified. Prior to PDT 2.5, VMCreator did not allow you specify timezone, so all VMs created used Pacific Standard Time. PDT 2.5 adds the ability to specify timezone, either as default across all VMs being created or individually by VM. To do this, just add a <TimeZone> entry to either the <Default> section of the <VM> specific section in Variable.xml. For example, since I live in US Central Time I include the following line in the <Default> section for my lab setup:
<TimeZone>Central Standard Time</TimeZone>
The list of timezone entries used by Windows setup can be found here – that page also states that this entry is always in English.