How to make smoke follow a spline with X-Particles?

hi everybody

I’m working with the X-Particles-plugin (version 3.5) in C4D R19 and came across the following problem. How you can see in the attachment file, I’ve used a xpDomain to produce Fire & Smoke. My goal is to use the xpFollowSpline modifier to let the smoke follow the Spline-Object. but for some reason it does not seem to work.

Do you’ve got any Idea how I could solve this problem?

Thx!
Lg formscope