I don't actually think the booster smoke follows you per se, rather it just has a set velocity in one of the four cardinal directions. Another issue that might come up is the fact that there's no support for transparency (DirectDraw7 doesn't support alpha blending), so the fading might look a tad awkward.
Basically I imagine you'd have to do it from scratch; create two entites, one for the "spawner" that generates an entity at the player position, and assigns the player frame to the direction. Then for the other entity just have it count down and change the frame # however you want so it "fades"
It wouldn't be monumentally challenging but for someone new to ASM it sounds kinda tough.