UI: Column ID vs. Column title

In 6.2, the following code snippet (in my VB6 app) was valid:

matMatrix.Columns.Item("Quantity)

for an SBO (non-userdefined) column.

now, I must use

matMatrix.Columns.Item(11)

to get my application to work for the same SBOcolumn.

However, for user-defined fields, I can still use:

matMatrix.Columns.Item("MyColName")

without error.

My question: Is there a way to universally reference columns in a matrix for ALL columns without having to use the column ID? It appears something has changed in 6.5?

Thanks,

Randy