Checking custom properties between template and document??

[ML]

I have a template that makes use of a number of custom document properties
to store data related to the document. The issue is that we may have new
versions of a template over time in which new properties are added. If a
document that was created from an older version of the template is then
linked to the new template then the new properties will not exists and thus
anything referencing them will cause an error.

Is there anyway to resync a document and template so that the custom
properties are the same? Or some means to loop though and compare the two
or is the only way to check for them on an item by item basis?

 

[Jezebel]

Add an AutoOpen macro to the template, that updates the document's
properties from those in the template.

But the situation doesn't quite make sense. If these values are constant,
why store them in the document at all? -- why not just leave them in the
template? But if they store data 'about the document' why do you want to
change them to the values in the template? -- what happens if you have two
documents based on the template, with different values?