During Import, there's a small dialog called import options that pops up just before the import starts. There's a check box there for enabling import options. If you enable import options on this dialog, you should see creation dates entered into your newly imported records date field. Please note that this enables all auto-enter options. Sometimes you can't use this options when it will also auto-etner data in another Field when you don't want it to.
In such cases, You can use Replace Field Contents to update the contents of a field just after you have finished importing the records.
Funny thing...... When I did a Replace action in a different field for the found set that was created after the import, it seemed to trigger both the Creation Date and the Modification Date.
All is good and thanks for quick response.