Thanks for your patience Espér.

I am really sorry, but i can't open the MED inside processing a lite-c script by the engine, and execute your advice and save the model and reaload. And moreover continue the running of the script.

I tried it explain in my starting post, it is a pity, nobody can't understand... (it was a really simple sentence)

The happier end of this thread is that, i have the fully working solution, naturally in lite-c.
No MED, no WED, only the engine and script.