Why do you not think this is possible? And what will going to /abuse/ do? or /info/ or /support/? These aren't native to OTRS.
Also it is not possibel to have more then one customer on a server,
because OTRS enforce to use ONE database instead one database per
customer and target.
I don't understand this, either. Of course OTRS supports more than one customer. What does "support more than one customer" mean to you?
You don't have to have an entirely different MySQL instance to run multiple instances of OTRS, either.
Further, why are you asking on the OTRS mailing list to tell you of another product?
How, specifically, may we help you?