WinXP with Word 2003 SP1...

How do I prevent the STYLEREF info from changing in an image caption? After
editing the ref, I check the box that says "Preserve formatting during
updates", but no joy.

I have modified the headers in the document to be based upon the default
Heading 1, 2, etc. with new style names (EOI Header L1, etc.).

When I first insert a caption and check the "Include chapter number" box,
the chapter portion of the caption always comes back as "Error! No text of
specified style in document". OK, so toggling the field code shows
"{STYLEREF 1 \s}". I right click and edit the field to make it "{STYLEREF
"EOI Header L1" \s}", click the Preserve formatting box, then update the
field. This places the correct style (and value) in the chapter section of
the caption. It looks fine!

However, when I edit the next caption, the previous image's caption has
reverted back to "Error!..." and the STYLEREF has reverted back to {STYLEREF
1 \s}... my edits to the field have disappeared.

What else do I need to do?