Francesco,

Seam uses a number of different variable resolvers. I thought there already was a jBPM resolver. Could be though that it only works in the scope of a task. If you are on a task list, you are not in the scope of an individual task.

Some remarks:
- I would not display all taskvariables on that task list. Will become very slow (to many queries to the db)
- put as little variables as possible in the task or even the process. Put as many as possible in your domain model
- just show someprocess-level info in the tasklist e.g. the businesskey (key on the processlevel

In this case you do not need the resolver you are talking about