Ok I got the message that my BP and Boa should not be together in one enclosure
First of all: this was just temporarily, next week their new home will be finished and they all will have a seperate enclosure. Everybody happy (including the snakes)
Second: the person from whom I bought the snakes (also a BP and Boa breeder) told me it wouldn't be a problem to put both of them together (I just trusted his judgement because he has a lot of experience with these creatures).
I joined this group to learn more about my pets, it's just is hard for me to understand everything because it is all in English (but I try).