88 colors don't work under GNU screen

[Serge Koksharov]

   Hi, dear urxvt users and developers,

I'm sorry if I'm little offtopic, but I saw people in this mailing list
using urxvt with GNU screen. Did anybody accomplished correct 88 color
displaying under GNU screen? I tried almost everything, nothing helps.
XTerm displays 256 colors correctly, but with urxvt I get first 16
colors OK, but all additional colors are shuffled. I use `88colors2.pl'
color test from XTerm distribution. If I didn't make it clear, I can
post screenshot somewhere and provide an URL. Of course in standalone
urxvt all colors are OK. I have:

Screen version 4.00.02 (FAU) 5-Dec-03
URxvt (tried different versions from 5.3 to the latest one)

I hope, somebody can help me with this trouble which annoys me so much.
Thanks in advance!

Sincerely yours, Serge

P.S. Also can anybody make it clear, why URxvt choose 88 colors, not 25
6 like in XTerm, or both color models with ability to switch them? 88
colors are enough for my needs, but there would be no harm with 256.