Column Configuration in KB31N

Team,

I need to add (Activate) one more column in KB31N List Entry 05SAP WBS Element, say 'Material Number'.

1. When tried to access 'administrator' in configuration (table setting) I can view many empty column with no column name and length as 0. Is there any way we can activate it (rename and assign lenth)

2. Can I get a column where I can directly choose the material number from material master (using F4 key)

Thanks& Regards/ Tony