Real-time shared Skydrive editing in Excel, not in Excel web app

A colleague and I can successfully simultaneously edit an Excel spreadsheet in Skydrive Web App but it is clunky, not much better than editing/formatting in Google docs. Can we both open the same spreadsheet in Excel and still edit simultaneously? (Able to see one another's changes by saving/reloading versions often? We are just working with text, not formulas.) We have done this successfully in the past with Word documents (edit simultaneously in Word view, not Word web app view), but are for some reason unable make it work in Excel. Any help you can provide would be very much appreciated! Snowdancer55.