Not sure I understand your use case here...
I would say that seam component could be more like a form of the user task instead of ftl. As you could make use of TaskClient API in your seam component. and interact with task server to:
- get tasks assigned to given user
- get details of the task when working on the task
- notify it about completion of the given task
ftl is just one implementation currently available by default in jbpm-console but in standalone implementations you could use UI framework of your choice.
HTH