Which date data - EXIF, XMP, IPTC - does AP read on import?

I'm importing some film scans and files created from digital cameras into my Aperture library. Most of them already have IPTC matadata added, this would have been done when the scans or JPGs were originally made.

I'm having trouble where the IPTC date and XMP are different. This will be because the IPTC date is the date the image was taken while the XMP date is the date the file was created. Aperture always wants to use the XMP date which is invariably the wrong date!

For example, I have a JPG file which - according to Photoshop's File info - was taken on 30 March 1997. Under the 'Advanced' tab in Photoshop CS5's File info I see:

photoshop:DateCreated: 1997-04-30

xmp:CreateDate: 2009-10-07

The xmp:CreatorTool is Adobe Photoshop Lightroom and the xmp MetadataDate and ModifyDate are the same are the CreateDate (which all include the time but I don't think that's relevent here). There is no other date metadata.

So I made this JPG by exporting it from Lightroom on 07 October 2009. Now when I import it to Aperture the IPTC Date Created is show as 07/10/2009, not 30/04/1997.

So Aperture is treating the file creation date (xmp:CreateDate) as the date the image was made? Which, to my mind, is wrong unless you only ever have digital camera files in your library. Or Lightroom was wrong to write the xmp:CreateDate as the date the file was created? But being as Adobe control this XMP space...

What do you think?