User exit for tcode MD04/MD06 exit-LMDR2001 and LMDZU001

Hi All,

I found these exit for transaction MD04 and MD06,

LMDR2001

LMDZU001

Here My requirement is when displaying collective access for MD04 or MD06, It will display material num, MRP Area, Mat Des....

Here before it display I need to replace the material with some alternative material corresponding to the original material.

I kept break point in the above user exit and when I run these transactions it is not stopping in the user exit.

Kindly suggest right enhancement for these tcode or any alternative.

Thanks in advance,

Arun Kumaran.