I'm using Microsoft Office Word 2003.

I have a document that was formatted for some ancient page-layout program
that won't even run under Windows XP, so I'd like to put it all into Word.  
It's currently in a tag-style format; for example, to italicize some section,
it needs surrounding tags, like this:

<W0I>Passage to be italicized.<D>

The document is huge, so I need to use Replace all to turn all of these into
italics in Word.  Is there a way to turn such passages, wherever they occur,
into italicized text in Word, dropping the tags on either side?

(I thought of trying to convert the document to HTML format, but there is a
killer problem:  Every formatting, whether bold, italics, or a change of
font, ends with the very same tag, <D>.  But HTML wants italics to end with a
</em>, bold to end with </strong>, and a font to end with </font>, matching
the opening tag.  I don't see how I can do that automatically.)

Perhaps I could use a macro; it would have to "turn on italics" when it saw
the <W0I> and "turn off italics" when it saw <D>; again, I can't figure out
how to do that from the Word help system.

Help!  This is a ginormous document, about 200,000 words.  I would go nuts
trying to do this all manually.  Alternatively, if someone can suggest a good
Word book that would explain to a dope like me how to do that, I would be
very appreciative.

Thanks,

Dafydd