Running mxmlc with .actionScriptProperties

I am not a FlexBuilder developer.  I only use command line tools with the SDK.

The mxmlc compiler indeed has an option that lets you direct it to a specific configuration file.

Run:   mxmlc -help list advanced | more

if you you want to see a pretty comprehensive [but not entirely complete] list of the options.  But you should probably Google for some more useful tutorial materials which will add explanations of what might be accomplished by each option.

In my case, for maximum productivity, I run the incremental-compilation-wrapper -- fsch.exe.  It, unfortunately, has treated AIR compilations as a poor second cousin -- so it does not recognize amxmlc.  But, since mxmlc has an option closely related to the one you want -- load-config -- that is called -- configname -- I can get the desired result; i.e., if some compilations are just Flex, but others are AIR, I can still use fsch.exe to execute mxmlc with the appropriate configname argument.

So, I am sure that FlexBuilder has files called flex-config.xml and air-config.xml laying around somewhere.  That is what you probably want to use as the starting point for whatever file you want the compiler to use.  So, that takes you to the feature of mxmlc which says"  "Hey, if I am compiling a source called Some.as or Some.mxml, I will look to see if there is a nearby file called Some-config.xml.  If there is, I will merge whatever compilation parameters I find in that file with whatever the base one i!"  That is another productivity improver for those of us who just live with the least-common-denominator development environment.