Using variable in persistence.xml <jta-data-source> leads to deployment-dependencies-error

Using variables in persistence.xml works (see AS7-3195). But if used within tag jta-data-source an error is show during deployment:

"jboss.persistenceunit.\"pdfWhitelabelServer.ear/pdfWhitelabelServer.jar#ipadDomain\" Missing[jboss.naming.context.java.\"${ipadserverds.jndipath}\"]",

(pdfWhitelabel is our product; ipadDomain is the name of the persistence-unit; ${ipadserverds.jndipath} is the variable defined as start-parameter for a node).

The goal is to deploy one deployment to different server groups (one server group for each customer) and the software should use different datasources in each server group for jpa ( neccessary to avoid resource-dependences between customer-instances).

According to our needs we use domain-mode but for completeness it doesn't work using standalone either.