User defined fields reference in Matrix VB6

I have a couple of user defined fields on the Delivery Details Matrix that I need to update. I know that I need to reference them by index as follows:

Set oEditText = oDelDetMatrix.Columns("Index").Cells.Item(ivlRowCounter).Specific

oEditText.Value = CCur(dvlSomePrice)

The problem is even if I check Watch window for the indexes I can not be certain what indexes to use for these columns. Is there a way to get exact index number?

Is there a way to reference matrix columns by by field names?