Limiting Moneydrop in certain region

Hi, i installed the plugin MoneyDrop, which works fine, and i'm trying to prevent money to drop in certain regions (so that player can't farm in mobtowers).
There is a plugin called DropGuard that is supposed to do that, but it doesn't seem to be working. Probably because it hasn't been updated for a year, but it could be because I did something wrong:
I created a region in worldguard, named it "mobtower". In moneyguard's config file, I added: Mob-Drop-Disabled-Regions: [mobtower]
I then restarted my server, but the mob are still dropping money in the "mobtower" region.
Did I do something wrong ?

Alternatively, if the problem comes from the plugin, is there a way to do it differently? Moneydrop has a permission node that prevent players from picking up money: MoneyDrop.pickup
Is it possible to deny this permission to players in the area, and then give it back to them when they come out of it ?

Thanks