[argyllcms] Please tell me I'm doing something wrong because I'm really starting to hate Photoshop!

I'm doing some tests with Argyll_V1.1.0_Beta gamut mapping.
This is the image I use for the tests:
http://darkbasic.homelinux.com/varie/argyll/IMG_3308.png

I have not achieved good results with sRGB as destination space, so
this time I used a real printer profile.
This is the printer profile (RGB, LUT, v2.4, 784KB):
http://darkbasic.homelinux.com/varie/argyll/305_pearl.zip

tiffgamut -d1.0 -pj -cmt IMG_3308.tif IMG_3308.tif
collink -qh -G IMG_3308.gam -ip -cmt -dmt IMG_3308.tif "30,5 pearl
fuji DP 3_2.ICC" link.icc
cctiff -d "30,5 pearl fuji DP 3_2.ICC" link.icc IMG_3308.tif
inprinterprofile.tif

This printer's profile is fully contained in my monitor's gamut, so it
should be perfect for soft proof tests, but it has a non-zero black.
Usually Photoshop kills kittens if I use a non-zero black profile,
this time it did something even worst!
The resulting image seems to be very good and if I convert it to
Prophoto (relative intent and BPC) with Photoshop there are no
noticiable differences (as I should expect).
But if I open both in Firefox 3.0.11 (it uses LCMS, do not use Firefox
3.5 because it uses QCMS which doesn't support LUT profiles like the
printer one) there are noticiable differences!
Why?! There were no differences in photoshop :'(

This is the image I obtained with Argyll:
http://darkbasic.homelinux.com/varie/argyll/inprinterprofile.png

This is the same image coverted with photoshop to Prophoto with
relative intent and BPC:
http://darkbasic.homelinux.com/varie/argyll/wasinprinterprofile_nowprophoto.png

Let's see what happens if I convert it back to the printer profile!!!
http://darkbasic.homelinux.com/varie/argyll/wasinprinterprofile_thenprophoto_nowprinterprofileagain.png
It's a night and day difference!

The gamut can obiouvsly fit the printer profile because it was in the
same profile before the conversion to prophoto!
Gamut warning confirms it.

Am I doing something wrong?
If not, I fear I'll have to switch to Cinepaint before going crazy :)

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