Marius,
You should look at the Event Structure in LabVIEW, and use that instead of the While Loop. With the current implementation you are polling the Save and Load buttons all the time in the While loop. With Event Structure you would get an event whenever any of these button's values change (after you set it up that way). Plus, with your Vb background, you will like Events
As for passing the array reference into the subVI and then using a Property Node, I guess it can be considered similar to using a pointer. But, you don't want to do that in LabVIEW unless you have a good reason. Because, Property Nodes execute in the UI thread (which is other than the diagram thread), and this will cause a thread-switching which is expensive. Here's a comparison of Terminal versus Property Node versus Local variable:
Local variable = 15 times slower than Terminal
Property node = 653 (!!!) times slower than Terminal
The above is from the following post: http://forums.ni.com/ni/board/message?boar...essage.id=90261
Depending on how long you will be working with LabVIEW, you may want to stop thinking in terms of C and VB, and start thinking in terms of data-flow programming.
Regards,
-Khalid