To avoid errors, rename the peripheral initialization component to a unique name! That's it!
This is done by first
--adding the inialization component, selecting advanced at the upper right, and then
--editing the name which is the first property of the component. You can for example add "my" as a suffix.
Then, you can use the PESL commands by dragging them in without generating compile errors.
(The root cause of this is a name space collision between header files generated by PESL usage and PEx generated code. But, you don't need worry about it if you do the above work-a-round.)