Story Array in SharedObject

Good day to you.
Can anyone tell me how I can store an array into a sharedObject? I m using this code:

_mySharedObject.setProperty("anArray", _myArray);

But on the Flash Media Server 3.5 I only get this message

Object encoding error; terminating connection

This is really bad…everything else works. I can add a Number or String as Property…only the array doesn´t work. Any ideas?