Libgdx + ios-moe xcode problem with 3rd Party library

After importing libgdx project to Android studio we do not see those multi os engine options in context menu to add 3rd party library.
Anyway we managed to compile our project using commandline gradlew :moeLaunch.
When starting the app from xCode the app shows splash screen and plays sound as desired. As soon as it uses one of our two external libraries the program crashes:

Excerpt of the stack trace can be found here:

Since we are not the xcode OSX guys we do not know exactly what to do.
Do we have to link the jar files somehow to xcode.
There are some compiled *.class files in xCode project under moe/build/moe/main/retro/output/.
Those concerning the game are under com. In other namespaces(packages) e.g. aurelionribbon are those concernig these used libs.
We realy do not know what to do… and seeking for help :wink:

Try add

-keep class org.apache.commons.logging.impl.** { *; }

in the proguard.append.cfg file.