Convert model with S-functions to dll

Hi.

I try to convert my Simulink model to dll (I used ert_shrlib.tlc as the target file). This model was developed by third party. The model contains three S-functions. But I have no source files for them (only mexw32-files).

My question is: Can I convert my model to dll, if I have no source files for S-functions?

I tried to solve the problem by writing my S-functions that would have the same number of inputs/outputs and would call inside them the mexFunctions of original S-functions. This solution (mexFunction call in other mexFunction) have been discussed at this forum. However, Simulink and Matlab work differently with mexFunctions… In short: I failed.

If anybody has ideas in this problem, I would be grateful for any help.