I have the pitts Slimline muffler (regular NOT smoke)

how can I convert it to "smoke"? I have the Skywriter smoke pump

On the smoke muffler the only apparent difference is a nipple on the side of the barrel.
Is there a some sort of coiled tubing to preheat the oil inside?

If anyone has converted successfully a reg. Slimeline muffler to smoke pls tell me how.

thanx