Not sure how you're attempting to force the date in your application, but the rules, while consistent, are a little complicated. Bottom line is that, at least in queries, Access will ALWAYS attempt to use dates in ##-##-#### format as mm-dd-yyyy unless that's a invalid date. (In other words, it will use mm-dd-yyyy for the first 12 days of every month, and dd-mm-yyyy after that)
See whether Allen Browne's International Dates in Access helps.
Doug Steele, Microsoft Access MVP
http://www.AccessMVP.com/djsteele (no e-mails, please!)
Co-author
Access Solutions — Tips, Tricks, and Secrets from Microsoft Access MVPs (ISBN 978-0-470-59168-0)