The crosstab you want to include as an attachment should have all those fields removed from the detail shelf, tooltips, rows, columns, etc. They can be filters if you need them there, but no where else. As long as they're on the trigger view, they'll do their job, but since you're attaching the other sheets as the CSV, just remove them from that sheet, and you should be good to go.
Wow, the solution was so simple. Don't know what I didn't think about it in the first place. Thanks a TON.