Penny,
LAS does not expect an init_script as part of the product_server properties, so that property is just going to be ignored. We didn't consider that somebody might want the opening plot to look different from what happens when you select that data set.
You might be able to accomplish having a custom opening plot by making a new "private" operation. Copy the operation that is being used to make the default plot in the operationsV7.xml. Give it a new ID and mark it with the private="true" attribute. You could then use that operation for the initial plot and customize it to your liking, but because it's "private" it would not show up as an operation when you select the data set. I haven't actually tried this, but something along those lines might be made to work.
Roland