If you need set the other value to your com.extjs.gxt.ui.client.widget.form.Radio that isn't the boxLabel.

MyRadio.java
Code:
import com.extjs.gxt.ui.client.widget.form.Radio;

public class MyRadio extends Radio {

	private String valueAux;

	public SfRadio() {

	}

	/*
	 * (non-Javadoc)
	 * @see com.extjs.gxt.ui.client.widget.BoxComponent#afterRender()
	 */
	@Override
	protected void afterRender() {
		setNewValue();
	}

	/**
	 * Real value of radio.
	 * 
	 * @return value of radio.
	 * @since 1.0
	 */
	public String getValueAux() {
		return valueAux;
	}

	private void setNewValue() {

		if (valueAux != null) {

			getInputEl().dom.setAttribute("value", valueAux);

		}
	}

	/**
	 * Set the new value to radio.
	 * 
	 * @param valueAux new value.
	 * @since 1.0
	 */
	public void setValueAux(String valueAux) {
		this.valueAux = valueAux;
	}

}
Example
Code:
	public void onModuleLoad() {

		FormPanel form = new FormPanel();

		final SfRadio radio = new SfRadio();
		radio.setName("radio");
		radio.setBoxLabel("Red");
		radio.setValue(true);
		radio.setValueAux("1");

		SfRadio radio2 = new SfRadio();
		radio2.setName("radio");
		radio2.setBoxLabel("Blue");
		radio2.setValueAux("2");

		RadioGroup radioGroup = new RadioGroup("test");
		radioGroup.setFieldLabel("Favorite Color");
		radioGroup.add(radio);
		radioGroup.add(radio2);
		form.add(radioGroup);

		RootPanel.get().add(form);

	}
History
07/01/09 - Remove the Listener and create an example