Providing the Additional Tab to MIGO_GI Transaction (item wise)

Hi experts,

I have a requirement to add the Additional TAB in the MIGO_GI transaction.for this i have used the BADI MB_MIGO_BADI.

I have provided the custom program name and subscreen no in method PBO_DETAILS and hence i am able to see the
additional tab for the subscreen in MIGO_GI transcation.

My Custom subscreen consist of 4 fields out of which 2 are editable. (like Field1, Field2, Field3 and Field4)

I want to SAVE these four fields for all the line item wise (materials in this case) in custom table during the MIGO_GI transaction POST/SAVE functionality.

Moreover i also want when user open the MIGO_GI transaction in Display mode then all these four fields for all the materials should be display with read only mode.

I dont have an idea on how to transfer these 4 fields value to the custom Z table during the document post and vice-versa during the display time.

Please suggest. (step by step would be more helpful)

Regards,
Jagesh