While dealing with basically the same problem as http://www.gossamer-threads.com/lists/modperl/modperl/97455 for https://sourceforge.net/projects/aepps, a lot of Googling and Source-reading brought me to the following solution:

    AcceptFilter epp none
    Listen 700 epp

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Now knowing the solution, I checked back to the official documentation for these two directives, and found that

* http://httpd.apache.org/docs/2.2/mod/core.html#acceptfilter
  does not somehow tell the reader how to set the protocol name for a socket.

* http://httpd.apache.org/docs/2.2/bind.html
  does not contain any information regarding a possible second parameter which sets the protocol for this port.

* I haven't found any hints as to what a connection-handler should do (e.g. call ap_set_server_protocol()?) to set the AcceptFilter or "protocol" field itself.

Phew. 

What about adding to the "Listen" documentation something like

"Listen takes an optional second argument which sets the protocol name for this connection. An 'AcceptFilter' statement can then be used to set policies for this port"

and to the 'AcceptFilter', something like

"The default protocol names are https (for port 443) and http (for everything else). To set the protocol of a specific port, use the second parameter of the "Listen" directive.