We have not used PlanView but are working a project to integrate Windchill with MS Project. The mechanism for transferring data between MS Project and Windchill is xml using MS Project's XML schema. Maybe see what neutral format PlanView uses for data transfer? If it is compliant with the MS Project schema, then try exporting out as XML and see how it loads into ProjectLink.
One of the things I found though is that the PJL XML isn't 100% compliant with the MS Project schema. For example, a task's unique ID is the same as the task ID in Windchill, so if you delete or reorder activities in Windchill and then export to project, it takes the current PJL ID and makes that the unique ID.
Unique ID may be important if you are tracking activities by their originally created ID that does not change in MS Project for example.
Lets say you create tasks 1,2,3,4 and they have an ID of 1,2,3,4 and Unique ID of 1,2,3,4 .... if you delete task 3 in project and create a new task, say "5" the ID & unique ID's would be as follows 1,2,3,4 & 1,2,3,5 respectively. If you do it in Windchill and export via XML they will be 1,2,3,4 and 1,2,3,4.
Some other caveats to think about is calendar/scheduling. Windchill doesn't allow use of anything but the standard MS project calendar, and uses Windchill calendar working days / holidays for scheduling calculations, so you might need to make sure calendars match as well before the XML will properly import.
Lastly, There is a bug (at least in 12.0.2.x, 12.1.x etc) where if the imported plan has ANY warnings (you are supposed to be able to acknowledge and import with warnings - errors are a hard stop) where the temp file is removed from the WC temp file location on your WC server file system before you can acknowledge the warnings and complete the import... so your plan has to be PERFECT to be able to import.
