Hello Anitha!
One time, i need to do the same thing, and i used to help me this link information and link below!
Try to do this:
1. It says that you need to copy the standard interface into your Function Group (Group which contains the Table maintainence)
If you open your group in se80, you will not able to find the GUI status. Because system doesn't contain the PF stautus. It refers to the PF status of the program SAPLSVIM. So, Copy all the PF Status into your Function Group.
2. After copying you need to add your buttons in the respective PF-status. You can create your own PAI module and handle the PF status button.
Add Custom Button on Maintianence View (SM30) | ABAP Help Blog