I assume that the mixing problem occurs when you need to use the mx classes. *, but you are in a pure as3 project.
as3, flex ActionScript, .
Flash, SWC actionscript ( ) flex.
, -, , Component Kit.
Flash IDE ( , , - ), mx. *, HTTP, . , flex - , , , ... , ...
, , , ... flex , , .
as3 WebService, .