When using the Dialog Builder, FotoStation now shows you the IPTC field numbers of the fields placed in the editor:
 

 
This can be particularly useful when creating a dialog for a heavily customized metadata configuration, with many custom fields.
 
Caveat lector: I used to work with support at FotoWare. This blog is my own space, I am not paid to write it. I write about FotoWare and FotoWare products because I believe in them.