Hi ,
You can try TCODE SMOD. Put the enhancement 'CNEX0026'. Then display it. Click the 'Components' button. find the Function Module 'EXIT_SAPLCOMK_005'. Double click this FM. Have a look at the import parameter. Write code in the include 'ZXCN2U06'. Double click this include. if it create code first time. there will be a worning message. Ignore it. Just enter. Then you can enter which you want to implement function.
If you want to active the enter code function, please go to TCODE CMOD, create a project, Click the 'Enhancement assignments' button, entre the enhancement 'CNEX0026'. Then active it. It will work well.
Regards,
Yawa