In order to enable the use of the local administrator via a K2000 scripted install you must modify the answer file to include the below statement.

</RunSynchronousCommand>
<RunSynchronousCommand wcm:action="add">
<Description>Enable Administrator</Description>
<Order>2</Order>
<Path>net user administrator /active:yes</Path>
<WillReboot>OnRequest</WillReboot>
</RunSynchronousCommand>
</RunSynchronous>
</component>

Note: Only the info in bold will need to be added the rest of the statement will already exsist.