Jesper Kiær  has posted a very compelling video showing how the HTTPEnableConnectorHeaders = 1 notes.ini parameter can be used to gain access to Domino servers.
We no longer use the Apache proxy scheme as the SSL support in Domino has improved but I tested this on one of our development servers by setting HTTPEnableConnectorHeaders = 1 and using the “Modify Headers for Google Chrome” extension and was able to get access.
As Jesper notes many of the write ups about using Domino behind a proxy specify using this setting. There are some useful comments to the first post in Jespers series on this issue.