The PubCenter section of the Pipeworks manifest describes how PubCenter ads will be placed in a Win8 application.
Like the AdSense section, it requires an ID, and a BottomAdSlot or TopAdSlot are supported:
Here's an example:
@{
PubCenter = @{
ApplicationId = "1b9271e7-0be4-4ef1-84c3-9e8f921c1b4a"
BottomAdUnit = "10048228"
}
}