1. Open JBoss Server View
2. Double click on the server there
3. See "Deploy" section. There is "Use worspace metadata" is used by default. You can switch it to "Use the JBoss deploy folder" or "Use a custom deploy folder".
-> Might a reason be that I am locally using the "JDK6" version of the AS while the productive server uses the "JDK5" version instead?
You have to set "Preferences -> Java -> Compiler -> Compiler compliance level" to 1.5 for your projects. Otherwise you will have errors in JVM 5.0 (see JBoss server log).
If you want an archive you can copy to a production server use File > Export > War (or Ear)