Thank you for your quick answer.
As you said, it seems there are only two general ways:
1. Reducing the mission time (deleting the first part), but maybe harder due to the connections between first and last.
2. Reducing the mission difficulty, to pass it easier but whole mission though.
I'm thinking about you said about savegames, but it need a question:
When I do preview...my scripts are loaded to memory in that moment? or in the moment when are called?
If they were loaded when called (not at the begining), then I could put a savegame just before the calling script (or press Save manually), then modify the script, load the saved game, test it, modify it, load the saved game, again and again.....
TIA
JF.