Hi Fabian
If you have attached any files here they are not visible.
The first question would be what is the error you are gettinng in the BPC Connection Wizard?
Second - are you able to run the connection wizard by specifying 123.52.60.200 or 123.52.60.300 in the servername field?
Third - are you able to load the http://123.52.60.200/osoft and http://123.52.60.300/osoft in the browser on the Citrix client?
Fourth - can you capture an http trace with Fiddler running on the Citrix server while running the BPC connection wizard and attach the fiddler trace here?
This SAP note may be useful 1629304 - In a load balanced environment one or more BPC application servers can not be accessed directly
https://service.sap.com/sap/support/notes/1629304
Stefan