Printing with different aspect ratio (or, How not to crop when print?)

Hi all,

I'm trying to print 3:2 aspect ratio pictures on 8 1/2 X 11 (US Letter page).
Obviously, it's not the same aspect ratio, so normally fitting such 3:2 image in, -say- photoshop would require me to either CROP the picture or have white BORDERS around it, on either side.

Now, printing in iPhoto will only offer croping, which is definetly not what I want. I can and will live with 2 white bars on my picture; I do own cutting table just for that. But I'm not used to iPhoto.

Quickly, in Aperture I can print as I want it, 2 white bars, whole picture fitting IN the paper (there's also a mode called 'Fill Page'; which is exactly and only what iPhoto is doing).

*The question:*
Am I missing something out on how to print while fitting the whole image on paper (also called 'Fit Entire Image' in Aperture), while adding white paper bars?

Also, I readed this thread, mostly about it:

http://discussions.apple.com/thread.jspa?threadID=1417869

I knew the maths part.
So what I'm doing as a long workaroung (see below for shorter workaround):
I calculate using the custom Print size (see this screenshot, from user Old Toad, which is exactly what I'm telling about: http://homepage.mac.com/toad.hall/.Pictures/Forum/iP7customprint.png ) manually, so I get as Paper Size : US Letter and as Print size: Custom with these custom settings:
Width: 11.00 in
Height: 7.30 in
It's all fine, the print was perfect. But I don't feel like messing each time with these numbers only to print one page.

Quicker solution: import into Aperture (and even there, if you are using RAW in iPhoto, the imported in Aperture is the JPEG based off the RAW ((apparently Aperture cannot understand iPhoto's way of working with RAW, but this is another topic)) ).

Thanks! Sorry, it was quite long for nothing, I'm just really missing the 'Fit entire image' on iPhoto... (that is, if it's non-existing, not if I only just didn't found it yet..)