Please be more specific. I don't thing anyone can understand your question.
Suppose the web sale order example that comes included in jbpm starters kit.
When the user creates a new web sale order, the task.jsp is shown and its form presents the textfields representing each variables of the associated task instance. The user then fill up those textfields and so assign the values to the task variables.
What I have to do it's just an add to that.
My task.jsp will not only show the form with the textfields representing each variable of a task instance, otherwise it will also present a dynamic empty table that will need to be filled up with data.
What is this data and where does it come from ?
It's define in a DataBase and are variables that contains the same fields that taskinstance variables
After filling up the static variables (defined for the taskinstance) I wish to add a dynamic variable so for ex. press some ADD button and a window containing all those dynamic variables will pop up and I'd choose one. Then the table would have 1 row.
How did I think to do this ?
By executing actions before entering those TaskNodes, and make those actions retrieve the dynamic variables from a DB in order to save them somewhere and access them via jsp mabe in task.jsp.