Actor property / MoML file

[Planat, Vincent]

Hi,

I need to generate automatically the .MoML file and run the Ptolemy simulation.
For that I need to set into the .MOML file a property that will be red by Actor 
when it starts.
I've added in the .MoML file stuff like that:
    <entity name="FiltersSim" class="ptolemy.actor.lib. FiltersSim ">
        <doc> Filter Simulator</doc>
        <property name="_location" class="ptolemy.kernel.util.Location" 
value="{195, 125}">
        </property>
        <property name="serviceId" 
class="ptolemy.actor.parameters.PortParameter" value="1001">
        </property>
    </entity>
The parameter that must be red by the FilterSim actor is "serviceId"
How can I read this parameter set into the ,MoML file from my Actor instance ?
All the example I found are defining in the Actor java code, a Parameter and 
use the .setExpression(...) method to set a value.

But in my case this is the reverse path I require. I need to set the value into 
the .MoML and just read from my Actor code when it is initialize() [or when 
Actor constructor is invoked ?]

Do you have a sample code for that ?

Thanks for your help

Cheers

Vincent