Is it possible to use an AMF Channel in a Flex HTTPService client application without using Adobe Livecycle, BlazeDs or similar in order to do real time asynchronous request from an HTTPService?
You can make an AMF HTTP call to any service that supports AMF. There are many options, both free and commercial.
FluorineFx http://www.fluorinefx.com/
AMF::Perl http://www.simonf.com/flap/
WebORB http://www.themidnightcoders.com/products
OpenAMF http://sourceforge.net/projects/openamf/
AMFPHP http://www.amfphp.org/
rubyamf http://www.rubyamf.org/
PyAMF http://pyamf.org/