How to write tlc-file for c-mex s-function

I am trying to run my simulation in Rapid Accelerator mode. This does not work, my simulink model contains a c-mex s-function. As far as i know, I have to write a tlc-file for my s-function (written in c++), to get my simulation running in rapid accelerator. Is there a different way to achive this? If not, how should I write the tlc-file? The c-mex s-function is very long, and i can not reproduce this code in this strange tlc-language. I really dont understand how to write these files, because there exist just a few usefull examples and there is not much documented in the MATLAB help.