I suggest you have a look here for a clarification concerning various flavors of LC data services (one of which id BlazeDS): http://gregorywilson.wordpress.com/2008/03/27/livecycle-ds-vs-livecycle- es-clearing-up-the-confusion/
Now if all you need is a function call/response patterm, amfphp should be just fine and much better than simple http services.
