Lookup Field in a Table, add an index

Hi

I have a table that contains a lookup field.
I was wondering if I can add an index on that lookup field so the user can
change the sort order of the grid linked to the table.

I have used Table.IndexDefs.Add('IdxName', 'LkupField',
[ixCaseInsensitive]), while I don't get an error. It also doesn't create an
index for me. The IndexDefs.Count stays the same.

Can you create an index on a "fake" field ?

Delphi 4 C/S UP #2
BDE 5.01
Access 97 (SP1)

Thanks
Jon