SQUID with HTTPS help needed!

Hi! I need some advice for squid! In our network is a Suse 8.1 with adsl on the net, with squid configured to be a transparent proxy for http, https and a non-transparent proxy for ftp. The ftp and the http are working fine but the https doesn't. The internal net can access squid ( the > telnet <ip> 443 is working ). A browser running on the gateway running the proxy can access the https pages on the web. But the browsers on the clients can't set up the secure connection. We are using NAT and IPTABLES to redirect the communication. Thank you for your help Aki