[C3] Can i18n transformer use an internal pipeline as bundle?

Hi,

I'm migrating a 2.1 cocoon application to 3.0, using beta1-SNAPSHOT
because I need the sql transformer.
As I wrote in the subject, I'm need to specify an internal pipeline as
bundle for the i18n transformer, because the properties file has to be
derived from database. Using a plain file it works.
I tried several urls using "servlet:" protocol, but without success.

I have the following internal pipeline:
<map:match pattern="translations_*.properties">

and I tried several bundles urls like:
<map:parameter name="bundle" value="servlet:/translations" />
or
<map:parameter name="bundle"
value="servlet:/translations_{jexl:cocoon.request.lang}.properties" />

The exception is:
org.apache.cocoon.pipeline.SetupException:
java.util.MissingResourceException: Can't find bundle for base name
servlet:/translations, locale en

What I doing wrong?

Best regards

Alberto