Word has only limited ability to do this.
You could create the field manually using CTRL+F9 to set the field
boundaries, then copy to the clipboard.
Use Replace to search for the text and replace with the clipboard contents.
(^c)

Signature
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Graham Mayor - Word MVP
Web site www.gmayor.com
Word MVP web site www.mvps.org/word
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> Hi All,
> I'm looking to use find and replace to find some text and
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>
> Martin