I'll try to include https support into upcoming 1.2.1 release, but in a meantime you can use http://www.stunnel.org/ to make it work.
Sample command line for stunnel3 (will listen on port 8888 for plain HTTP and connect to netxms.org:443 over HTTPS):stunnel -c -d 8888 -r netxms.org:443
Sample config for stunnel4:
client = yes
[http]
accept = 8888
connect = netxms.org:443
