The only Wacom pen that will work with your Xencelabs tablet is the Pro Pen 2 (KP504E). You will have very limited use of the Pro Pens side switches. They might or might not work.
We recommend you use either the Xencelabs Thin pen or the 3 Button pen for the most accurate connection with your Xencelabs tablet.
As a side note, the Wacom Standard Black and Hard Felt nibs will work with both the Xencelabs pens.