[squid-users] No keep-alives in connections cache<->servers?

While checking some of Squid's statistics thru' cachemgr.cgi, I noticed
that Squid reports "keep-alive ratio: 0%" for all my parents.

I checked FAQ for it: "This is a mechanism to try detecting neighbor
caches which might not be able to deal with HTTP/1.1 persistent
connections". This is very interesting, because my parents DO support
keep-alive (with both HTTP/1.0 and 1.1). I even checked it with
telnetting parents and manually tested by typing headers etc.

I have next settings in my squid.conf regarding to persistent connections:
     client_persistent_connections on
     server_persistent_connections on
     pipeline_prefetch on

Then I checked with packet sniffer that is Squid even sending those
"Connection: keep-alive" -headers to servers - but no.

Is there some kind of special way to enable keep-alives here? I tried to
understand the logic in sending those or not from source, but it would
take more time than I'm able to spend now.

Regards,

-- 
Pauli Borodulin
boro@fixel.org