Getting my 2008 XKR with 66K miles I've been checking everything out and one of the items I did was change the SC oil. In doing so I touched the pugged off check valve and it just fell off. Being my new car I though I would just order the new assembly for $40 -50. After reading some threads and looking at the setup I didn't need all the pluming. A trip to Ace Hardware I ran across some aluminon tubing for $3.00, Pictures tell the rest. Disregard the time stamps.

 

I have done something similar on my 07 by using a nub of the remaining line and sliding ~4mm inside diameter vacuum hose from O'Reilly's over the line and sealing using heat shrink tubing to bridge the slightly larger vacuum tubing and the nipple end, but was considering something like this for more permanence.

How did you get the bits of hard plastic line out of the rubber ends of the nipples to insert the tubing?

 

I used wood screw or a sheet metal screw.
Hope this works!