Enhancement not visible during runtime

Dear experts,

I have a problem with getting enhancements up and running in runtime.

I Changed 2 enhancements in FM J_1B_NF_VALUE_DETERMINATION and activated them. Activation goes fine, but for some reason during runtime (in debug mode), I can not see the code of the enhancement at all. My changes are not triggered, I can not even see the code in debug-mode. The complete code-block is missing. It seems that the enhancements are not active and are just not embedded during runtime. Do I have to activate something else? I guess CMOD and SMOD are not relevant in this case but if they are please let me know.

Thanks in advance

William