add project name column (sortable/filterable) in timesheet line grid

Hi,

I want to add Project Name column in the lines grid in TSTimesheetEntry form. You can access it from

Project Management and Accounting ->Common -> Timesheets -> My Timesheets -> select a record and open the form by double clicking it.

There is already ProjName column in it but it's a edit method which internally stores ProjId in the TSTimesheetLine table.

I tried to add ProjTable as datasource and make a join of it with TSTimesheetLine table and refer a projectname from projtable. i used outer join. but somehow while saving the record it wants to save the record in projtable. May be outerjoin is not the correct one.

This is what we do normally for List Page Grid. But this is entry form.

Can anyone please help me how do I make this proj name column sortable/filterable which is end goal?