passing 'date' data from external app to SP2010 date field

Hi, I am using SP2010 to store scanned PDF documents. The docs are scanned using Nuance ScanFlowStore, using a cover page with barcodes to route the docs to a document folder. I am trying to pass 'date' data format is plain numeric, NOT a true date value, but set as MMDDYYYY). The date data is input by my users and gets embedded in a barcode. I have 2 fields/columns in SP2010, one defined as datetime, the other as a single line of text. The text field gets updated with the 'date' data but not the datetime field. I need to have the date field updated so that SP2010 users can sort on the date column. I tried a calculated field using the text field as input, using Text(Date,"mm-dd-yyyy"), but the calculated field isn't sorting correctly either.

What should the date format be to update SP correctly?

Any suggestions would be greatly appreciated !!!!