Digital BW, The Print

Here's my slightly long story.  Been lurking and studying on this 
list for quite a while and learning as much as I could from the many 
experts, and other amateurs - with much thanks.  My background is 
scanning color slides with Nikon LS2000, minor adjustments with 
various incarnations of PS [now 7], and printing with Epson carts on 
my 1270 [for 5 years now].  I love my colors and my unsaturated 
prints [up to 12x18].  But they are dyes and [?] not archival, so I 
try UT with 1280 driver and Paul's new curves with desaturated rgb 
images.  My 1st test print on Epson HW matte was with the neutral 
curve and warmer than the Epson variation, but only slightly and 
pleasingly so.  Then I tried Somerset Velvet and used a cool curve 
and was satisfied.  Tried 3 different images on SV and they were 
progressively posterized and not at all like my screen image.  Only  
thing I can think of is that I used a hue/saturation layer to adjust 
highlights and shadows prior to desaturating layer, left image in 
rgb [flattened] and then applied Paul's curves.  Anyway, after 
waiting so long to make a decision about hextones I am very 
disappointed.  Any help would be appreciated.