Digital BW, The Print

I recently purchased and installed IP 5.6 on my Win 2000 PC, and am 
using it successfully to print very impressive images with my Epson 
2200. But one problem is driving me crazy. I print many 8"x8" images 
on 8.5"x11" (letter size) paper. When I select Letter Size paper in 
IP, I get a frame whose dimensions are "usually" 8.25"x10.25". If I 
create a user defined paper size, specifying 8.75"x11.75", 
I "usually" get a frame that is 8.5"x11". I have to say usually 
because I sometimes get even more strange dimensions. But regardless 
of the size I specify, or the displayed dimensions of the box, I am 
unable to get a print centered, no matter what combinations of right-
clicking or borderless or other settings I select.

This behaviour is so damaging to normal layout expectations, that I 
am sure it couldn't be a bug that Colorbyte has left un-fixed. It 
must be cockpit error (and I'm the hapless pilot).

So: Simple question: How do I get a centered print on 8.5"x11" paper? 
It can't be this difficult!

Kiefer Elliott
Vancouver, Canada