Hi, to avoid buying a siding nailer I bought one of these aftermarket flush drive attachments ($12) that fits Hitachi framing nailer and also my Porter-Cable FR350. Thought I would try it before spending the big bucks.

No instructions included with the attachment about how to install or use it.  Can anyone give me a clue as to how this gadget attaches to my FR350?

Here it is: http://www.amazon.com/gp/product/B002UJRORG/ref=olp_product_details?ie=UTF8&me=&seller=