Create a new PDNameTree for named Destinations

A week ago I knew nothing about pdf file internal formats or how to write an adobe plugin, but now I have successfully created a plug in to convert the bookmarks to named destinations and then export these named destinations to a text file.  I have one bug to fix, though, the situation where the destination name tree does not exist.  I could really use some help to finish this off.

Question 1:

So I use the following to get the name tree:

PDNameTree pdNameTree = PDDocGetNameTree(pdDoc, ASAtomFromString("Dests"));

My first issue is how to test for whether this is null.

if (pdNameTree == NULL)

and

if (PDNameTreeEqual(pdNameTree, NULL))

are not acceptable syntax.

So I'm using

if (!PDNameTreeIsValid(pdNameTree))

instead.  Does that seem like an acceptable practice?  Is there any other way to test if a Destinations name tree already exists?

Question 2:

After determining that there is no destinations name tree, how do I create one?  I see the function PDNameTreeNew in the API, but it only takes a single parameter, the pddoc.  How do I then take that newly created PDNameTree and associate it with named destinations ("Dests")?

Thanks in advance for your help!  I'm so close, I can taste it!