Being with a former reseller of AutoCAD, I'll chime in with a little info. One, the EULA for the German version MAY prevent you from running the software out of that county. We had clients based here in the US that wanted to take their license with them overseas, they had to get permission from Autodesk to do so, you may be in the same situation. Second, the old clean out the registry to install another copy of the trial version does not work any longer, the info is burned into the motherboard. You will need to replace the motherboard every time you want to install the trial version again. (Autodesk and Microsoft created this, if you're using Mac versions you might be able to bypass that.
I'm with ReMark, if they don't want to get you a license for AutoCAD then go with one of the other CAD packages for free.