I need a bit more info here. Are you creating a biography with one of the word processor plugins or through some other means? What do you mean it is no longer considered a bibliography?
Taking a guess, I would hazard you are trying to copy references from one Word document to another and you want those references to still be linked to your Zotero database when you paste them into the new document. I believe this would be a difficult if not impossible feature to implement.
Sorry for the lack of information. I use OpenOffice 3 and the last Zotero plugin. I created a document with a bibliography and some citations. Then I copied the entire content in another document created using a different template. After copying, if I put the cursor inside the biblography and click the button to edit it, the plugin tells me the cursor is not inside a bibliography. In this sense it is no more considered as a bibliography.
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Taking a guess, I would hazard you are trying to copy references from one Word document to another and you want those references to still be linked to your Zotero database when you paste them into the new document. I believe this would be a difficult if not impossible feature to implement.