Pseudo Resources

I'm having problems getting pseudo resources to work.

I've written a format plug-in and I'm trying to store
some text from the file header similar to the history
resource in the SimpleFormat example.

When I add the resource, I get no errors. If I check
the resource count, it shows it has been added. However,
whenever I save the file, the resource count always
returns 0.

What am I missing? I just need a place to preserve some
text from the file's header.

Thanks.

Photoshop CS2 SDK, OSX 10.4.2