After you set
in your build.script, to unlock save/loading the game will crash when you want to play the only scenario that is in the beta Part with Petrol. I have found a workaround it so the game will not crash anymore and you can actually play that scenario
go into Cities in Motion\metro\ui\menus\ and find scenarios.script open with notepad and look for this:
and replace with
and save the file. Go play the scenario that was crashing the game 
Code:
$beta = false;
go into Cities in Motion\metro\ui\menus\ and find scenarios.script open with notepad and look for this:
Code:
if (MAIN.$build.$beta)
Code:
if (MAIN.$build.$beta == false)