OrangeCD provides a date, so I really don't understand your question. Here's a list of some of my backup files:

myCDCollection_Apr_29_2005.bak
myCDCollection_Apr_19_2005.bak
myCDCollection_Apr_9_2005.bak
myCDCollection_Apr_3_2005.bak
myCDCollection_Apr_2_2005.bak

Isn't this what you're looking for? Or have I misunderstood your question completely?