Image Date Created not recognized

For whatever reason Vista ignores the true "Date Created" for an image
and assigns the "Date Modified" as the "Date Created". At first I
thought it was a technical issue with PaintShop Pro but the tech
supported pointed out the images, after saving and then re-opened in PSP
show the correct "Date Created". For some reason the date created is not
recognized by Vista. This makes it difficult when sorting by date
created. MS support were unable to help me and not sure where to find a
fix for this issue.