Workflow model question

[mangar]

I have a workflow that has a user task,  that takes in a text field, and I want to print it to the logs.  I have a form key and model that look like this:

 activiti:formKey="someco:getMessageTask"

<type name="someco:getMessageTask">
   <parent>bpm:workflowTask</parent>
    <properties>
        <property name="someco:message">
            <type>d:text</type>
            <mandatory>true</mandatory>
            <multiple>false</multiple>
        </property>
    </properties>
</type>

I have have a then a sequence flow to the end event, and all it does is write to the log.  It looks like this

    <sequenceFlow id="SequenceFlow_2" sourceRef="EnterMessageTask" targetRef="EndEvent_1">
      <extensionElements>
        <activiti:executionListener xsi:type="xsd:anyType" event="start" class="org.alfresco.repo.workflow.activiti.listener.ScriptExecutionListener">
          <activiti:field xsi:type="xsd:anyType" name="script">
            <activiti:string xsi:type="xsd:anyType"><![CDATA[logger.log("Hello, " + someco_message + "!");]]></activiti:string>
          </activiti:field>
        </activiti:executionListener>
      </extensionElements>
    </sequenceFlow>

When I try and start the workflow,  I get an error message:  (As a site note,  I get this error as soon as I start, it's like alfresco compiles the script before running, which to me, it the exact opposite of what a "script" is)  

"someco_message" is not defined. (AlfrescoJS#1)

Now when I start the workflow with that variable (in the admin console,  "start someco_message=AMessage"  it works fine.  

But why?  I defined that variable in the model for the previous task.  If that's not the way to do it  (And im pretty sure it's not)  What is the point of a task model?  Is there a good tutorial/explanation on how to handle data in a workflow?

[cristinamr]

The problem, as fas as I understand, is this:

<mandatory>true</mandatory>

If you have that property declared as mandatory, in order to launch the workflow that property should have content. For that reason is you launch from admin console, "start someco_message=AMessage"  it's working... because you are full fill in.

Check this guide made by @jpotts you have a really nice examples where you can start to learn how to make them properly.

Cheers.