In out company, we are using rtf file as common base for our many OpenOffice 
user and few MS user.

If I make a new document in MS Word with a field {FILENAME \p}, then Word can 
tell me path and file name.
I save the document in RTF format, close the document, and then open the 
docoument again in MS Word. The path and file name is displayed.
When I open the document in OpenOffice the field is converted to:
User field FILENAME \p=C:\testfile.rtf

so the field is converted to a static field.

If I make a OpenOffice document with a "Path/File name" field then Oo can tell 
me path and filename.
I save the document in RTF format, and close the docoument. 
When I open the document in OpenOffice the field is converted to:
User field \FILENAME=
and nothing is displayed.

If it possible to import/export a field i MS Office, so I think that it also 
should be possible in OpenOffice.