You can use Ant to generate ActionScript and Java classes from your FlashBuilder and LiveCycle Workbench ES2 models. All you need is a model (.fml) file (obviously), Ant (obviously), some jar files in your classpath (provided with LiveCycle Data Services ES2 and LiveCycle Workbench ES2), and the documentation for the Ant commands.
What documentation, you ask? You won’t find it in the core Data Services ES2 documentation, but Matt Butler put together a tidy reference in his blog. He explains how to extract the required libraries as well.
Product documentation is here.
Have fun generating those oh-so-useful service classes in your builds!