Ian,
I don't know that you would be able to do this. What it seems like is
you would like to call Update and Fill together, except, that you are going
to update some of the columns in the data table with the return values from
the stored proc, in addition to filling the array.
I don't think that you will be able to do this with the data adapter
alone.
If you can wrap your stored proc so that it returns all of the values in
the stored procedure parameters, then it would work, because then you would
define your Update/Insert/Delete command to map to your columns (in the
parameters, you set the source column), and when the stored proc returns, it
should populate the row correctly.
However, as is, you would have to write custom code to do this.
Hope this helps.