BPM to default the Backflush checkbox in the Part Master as TRUE


I am a newbie to BPM's and would like to start diving into creating a couple of defaults on the Part Master when a user goes to create a new Part. I am having an issue when attempting to default the Backflush checkbox under the Plant tab in the Part Master as checked on all newly created Parts. Here is what I am doing:
I go into BPM - Method Directives I select the Method Code: Part.Update
I then select the Pre-Processing directive and choose the following Action: set the PartPlant.BackFlush field of the changed row to the true value

Do I have to have a Condition?
For the value "true", does the case of the letters matter?
Is this a Post-Processing directive?

Thanks in advance for any help!!!