InfoPath Dev

I created a form with a drop down menu that uses a data connection to a Sharepoint library to select the starting date of all weeks on 2012. However, I have to adjust the values in the list to YYYY-MM-DD in order to make a formula I added to the day fields to automatically calculate each day's date. I know this is the only format XML supports to store the data but I'd like to know if there's a way to display the data in MM-DD-YYYY format on the drop down field without breaking the formula; or is there any other formula that I can use to get this to work?

You could add another column to your SharePoint list with the date in the format you'd prefer, and use that column for the Display for your drop down, the other for the Value.

Or you could use substring functions in your default value to put the date back together - here's a sample form that has some different Date formulas that might help you.