Poor performance using Netscape Proxy

Hello all,

I have 2.2S5 running on a Solaris 2.6 box (Ultra) and I am experiencing
a (quite) strange performance-related problem. Squid is configured to
use nothing but the basic proxy support, i.e. ICP, HTCP, digests e.t.c.
are not enabled. Some origin servers are directly accessible. For those,
performance is actually quite good. Unfortunately some domains are only
accessible through a Netscape Proxy (ver. 3.5). In the latter case,
squid performance drops dramatically. HTTP connection and object
retrieval seem to take forever to complete. As far as I know, this is
*not* a netscape problem, since my older HTTP proxy (Jigsaw 2.0.3)
cooperated just fine with netscape.

Any pointers/hints?

TIA
Mike