User Exit CY190001 for CM25

Hi,

While searching User exit for CM25 i found one exit CY190001. Hope this exit will help me for my purpose. When i went to 'where user list' for function exit EXIT_SAPLCY19_001 i found that function CY01_USER_EXIT_PLANNING is using this function exit. But the function CY01_USER_EXIT_PLANNING is not called by any program. I provided one push button on application tool bar of CM25 Tcode output. When i press this button i want to function exit EXIT_SAPLCY19_001 as to be execute. When i press the button which i provided it is going to program SAPLPLAT. but i dont know where SAPLPLAT is calling the function CY01_USER_EXIT_PLANNING. Could you please help me weather i can work with this exit or not ? Right solution will be awarded......

Thanks,