Please describe the problem:
Saving in Microsoft Excel 2007 format does not save the date cell-formatting

Steps to reproduce:
1. enter some date in a cell (e.g. 8/7/2009)
2. save file as Microsoft Excel 2007 format
3. close and re-open file
4. the date formatting lost, and in the cell remains a general format number (the count of days from 1/1/1900)


Actual results:
application works normally

Expected results:


Does this happen every time?
yes

Other information: