it looks as it's working anyhow, but i need to create different instances with different router-id's to have two sessions between two routers. Doesn't matter that they are different address-families. What a pain.
The as-path filters that i filed a bug report in August about are still not fixed and it looks like, that I can't filter on IPv6 prefixes, either.
Looks like I'm going to kick this box to h*** soon and replace it with something decent. Mikrotik might be good at wireless, but in regards to routing, it doesn't look pretty.