Variables saved with the variableDefinitionManager in one stage should be available in later stages

Use case

A task may define some custom build variable that would need to later be retrieved in subsequent tasks.
The current mechanism to handle this is to share artifacts between the tasks - the problem with this approach is that the "native" bamboo tasks, such as the ant task could not access this "custom build variables"; we would need to write a wrapper script that parses the artifact then invoked the ant command.

Tested case

I created custom build variables using the variableDefinitionManager

VariableDefinition vd = new VariableDefinitionImpl();
vd.setPlan(plan); 
vd.setVariableType(VariableType.PLAN);
vd.setKey(k);
vd.setValue(v);
variableDefinitions.add( vd );
 variableDefinitionManager.saveVariableDefinitions(variableDefinitions);

what currently works:

*Pass variables between tasks

   Plan
      Stage 1
          Job1
              task 1A: set_plan_variable myVar
              task 1B : print_variable myVar

What does not work:

• Pass variables between a jobs (expected not to work since jobs can be concurrent)

• Pass variables between a stages

     Plan
        Stage 1
            Job1
                task 1A: set_plan_variable myVar
        Stage 2:
            Job1
                task 2A : print_variable myVar