I've resolved this a "new" way, and posted on the BOB forums too:
http://www.forumtopics.com/busobj/viewtopic.php?t=143858
================= CONTENTS =============
The password trick did not work for me (BI4 SP4), but I was able to get around it.
1. Save workbook out to an XLS file
2. Using OpenOffice, save it as an ODS file
3. Upload both XLS and ODS to Google Drive asking it to convert to GDocs format
4. note: the XLS will likely fail with a >400,000 cells error (huh???)
5. Download the now converted ODS file back as an Excel document
6. Import back into Xcelsius
It's crazy, but it has worked consistently for the last couple weeks for me here.
