From their FAQ:

"2) Can Poseidon generate C++ code?

The standard templates provided with Poseidon can be used to generate Java and HTML code. With the Developer and Professional Editions, you can modify the code generation templates and even create your own custom templates. Code generation in Poseidon is based on the Velocity template engine. Using the Velocity template language and the Poseidon code generation framework, you can generate any kind of code you like, including C++ code. Please refer to the documentation for more information on customizing the code generation."