I'm looking for the (official MS) guide to scripting Excel with Applescript. I found one for Word from same era but not Excel. Even four MS support staff (three calls) can't find anything for me, in fact they don't even bother looking.
A document called "MicrosoftOfficeforMac2004ResourceKitv2" links to the microsfot.com/mac page and says goto Resources > Developer Center > AppleScript Resources for Office 2004 section. It doesn't exist any more.
Give this a try, it's what i've been using lately:
http://download.microsoft.com/download/3/A/7/3A70FB4B-0C6A-43E3-AAB7-AC9166B25632/Excel2004AppleScriptRef.pdf