Problem with root mapping rules and root template not created

Hi,

My problem is to define a generator for a DSL2 which uses concepts from DSL1.
I have in DSL1, a root concept called Machine.
I have in DSL2, a root concept called Application.
I tried to define a root mapping rule in DSL2 :
concept Application –> <no_template>
When I select intention "New Root Template" and select Machine (from DSL1), I have this result :
concept Application –> <no_template>
and new node in generator model :
(N) machine              (root template instance with Machine concept instance)

And completion in root mapping rule on <no_template> is empty.

When I create this test case from scratch with just empty concepts and with no dependence to other languages, it works normally :
intention New Root Template does :
concept Application –> map_Application
and in model :
(N) map_Application       (root template instance with Machine concept instance)

So the difference is the name of the created node (no prefix map_) and the root mapping rule which is not completed (and can't be completed).

There is something which prevents this edition in DSL2 generator. I don't know why, I added lot of dependencies to DSL2 to match dependencies of DSL1 but with no luck.

Can you tell me what can be the problem please ?
What can prevent generator definition ?