I have been looking at this question this morning, and had difficulties with accessing the vba project as it returns a trust error.
You may want to look at the link at the bottom, to see if you can figure out a way round this.
I have a feeling though that unless the original modules have been code signed then it may not be possible. It may be done this way to prevent a virus from self replicating into other documents.
http://www.cpearson.com/excel/vbe.aspx[
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