actually you probably should have one option name (Download) and one option value (zipped mp3) and then you would goto the attributes controller and using the dropdown pick the category you want to work with. Then the list of products in that category appear, pick the product you want to work with and click the display button. Now in the adding new attributes section highlight the option name and option value in the lists, if your product is base price only ignore the price/weight section, in the flags section make Default Attribute to be Marked Selected to yes, and finally at the bottom is the place to put the filename and expiration info for the download.......then hit insert.
All of your downloads will use the same option name and value they just have a different filname.......
Mike
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