Colour Profile change after Exporting a version

Hi

Has any one had this problem - and found a solution?

My Aperture Preferences are set to - Adobe RGB 1998.

Now,

1 - if I select an image in Aperture then select EDIT WITH ADOBE PHOTOSHOP

the image is opened in p/s

when I view the image in Bridge

the colour profile is correct - Adobe RGB 1998

Problem:

2 - if I select an image, then EXPORT A VERSION (to my desk top)

the colour profile changes to sRGB ?

Don't understand why this is happening - anybody know why?

Thanks

Tony (from London)