field value not populated in the input document received from trigger

I was trying to build a simple publish-subscribe solution using Broker by following the guidelines in Publish-Subscribe Developer’s Guide.
Following is what I did.

  1. first built a new document type which contains only one string field called filename. I then publish the document by setting the publishable property to true. everything else is left as default.

  2. built a processing service that has only one step which implements the build-in service pub.file:getFile that requires the input of filename.
    In input tab, I created a document reference that points to the published document type created in step 1. In the pipeline tab, I created a mapping between the filename of the input document to the filename of the service-in.

  3. defined a trigger in the same folder that associates the published document to the service that process the published document.

  4. synchronized the publishable document type by pushing it to the Broker.

  5. Then I ran a test of the trigger by supplying an input value to the only field in the publishable document, which is the filename.

I looked at the error log of IS server administrator, I saw the error of
pub.file:getFile com.wm.app.b2b.server.ServiceException: [ISS.0086.9019] No filename supplied.

It appeared that wm.broker.util.testTrigger invoked my processing service, which called the built-in service “getFile”. Looks like the document was passed in but the value was not populated.
I would be very appreciated if someone could take a look at my steps and point out what I missed or did wrong. I am new this webMethods so any suggestion is welcome.

I am working on webMethod 7.1.2.

Thanks.

I added a SavePipelineToFile step at the beginning of my processing (subscribing) service. I found out the value of the filename field was populated all right. The value was actually lost when I associated (linked) the filename of the document reference to the filename of the built-in service (getFile) in the pipeline tab. It seems that I just can’t assign the value like that.
I will update again as I find out what step I have missed.

The trigger’s “Document Type” must be the exact same name as the input document reference name. E.g. Trigger Document Type: “MyBroker.broker.docs.BDoc”, and Service input Document Reference name “MyBroker.broker.docs.BDoc”.

If the name is not correct it will all show in the pipeline, but not be assigned correctly.