is it possible to integrate ZEST with ZK normal MVC especially with GenericForwarComposer?

...
If the action generates the output directly to the response, you could specify the type as done, then ZEST won't handle it further but returning the response directly....

<?xml version="1.0" encoding="UTF-8"?>
<zest>
	<action path="/hello" class="org.opentruuls.base.rest.MyZestAction"
		method="execute3">
		<result name="success" type="done" ></result>
	</action>
</zest>

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

import org.zkoss.zest.ActionContext;

public class MyZestAction {

	/**
	 * EN: Gets the response from the ActionContext and gives back directly a
	 * string.<br>
	 * DE: Holt den Response aus dem ActionContext und gibt ein String zurueck.<br>
	 * 
	 * @param ac
	 * @return String
	 * @throws IOException
	 */
	public String execute2(ActionContext ac) throws IOException {

		HttpServletResponse response = ac.getServletResponse();
		ServletOutputStream os = response.getOutputStream();
		os.print("Hallo");

		// de: Niemals das Flush vergessen, sonst ist die Ausgabe unvollständig
		// en: Never forget to flush the output to clear buffers
		os.flush();

		return "success";
	}

	/**
	 * EN: Gets the response from the ActionContext and gives back directly a
	 * string as properties.<br>
	 * DE: Holt den Response aus dem ActionContext und gibt ein String als
	 * Properties zurueck.<br>
	 * 
	 * @param ac
	 * @return String as Properties (Key-Value pairs).
	 * @throws IOException
	 */
	public String execute3(ActionContext ac) throws IOException {

		HttpServletResponse response = ac.getServletResponse();
		ServletOutputStream os = response.getOutputStream();

		// write a property file with the needed data
		Properties p = new Properties();
		p.setProperty("Servername", "TomcatInstance_2");
		p.setProperty("Sessions", "134");
		p.store(os, "");

		// de: Niemals das Flush vergessen, sonst ist die Ausgabe unvollstaendig
		// en: Never forget to flush the output to clear buffers
		os.flush();

		return "success";
	}
}

   . . .
				final String urlString = "http://localhost:8082/opentruuls/hello";

				try {
					final URL url = new URL(urlString);
					final HttpURLConnection conn = (HttpURLConnection) url.openConnection();
					// inform the connection that we will send output and accept input
					conn.setDoInput(true);
					conn.setDoOutput(true);

					System.out.println("responseCode: " + conn.getResponseCode());

					final InputStream inStream = conn.getInputStream();

					try {
						Properties p = new Properties();
						p.load(inStream);

						System.out.println("count of key-value pairs: " + p.size());
						String s = (String) p.get("Servername");
						System.out.println("Value of Key 'Servername': " + s);
						String s1 = (String) p.get("Number of sessions");
						System.out.println("Value of Key 'Number of sessions': " + s1);

					} catch (final NumberFormatException e) {
						throw new RuntimeException(e);
					} finally {
						inStream.close();
					}
				} catch (FileNotFoundException ex) {
					System.err.println("Failed to open stream to URL: " + ex);
				} catch (final IOException e) {
					throw new RuntimeException(e);
				}

. . .
2011-12-21 21:59:45,126 INFO   [ContainerBackgroundProcessor[StandardEngine]] ContextLoader M - Root WebApplicationContext: initialization completed in 11173 ms
...
responseCode: 200
count of key-value pairs: 2
Value of Key 'Servername': TomcatInstance_2
Value of Key 'Number of sessions': 134