Other ways to increase bulk copy performance are:
Set the trunc log on chkpt option to keep the transaction log from filling up. If your database has a threshold procedure that automatically dumps the log when it fills, you will save the transaction dump time.
Remember that each batch is a separate transaction, so if you are not specifying a batch size, setting trunc log on chkpt will not help.
Set the number of pre allocated extents configuration parameter high if you perform many large bulk copies.
See the System Administration Guide.
Find the optimal network packet size.