In the task properties, go to "Output File Details" in there you'll see "Advanced Scripting Options". The code in there is the code that actually opens the file and then saves it.
The command to change the view to isometric will look similar to this:
swModel.ShowNamedView2 "*Isometric", 7
This line should go after the:
Set swModel = swApp.OpenDoc7(swDocSpecification) *
The actual code may vary depending on the view id of your Isometric view...and assuming you have an view named "Isometric" saved within the file.
(*Assuming PDM 2017 SP4, the default code in the advanced scripting options sometimes changes.)