I saw an example here: http://www.vcoteam.info/learn-vco/vcloud-director-vapp-hot-clone.html
Which suggested I do the following:
vApp.name = "asdfasdfasdf";
vApp.update();
This returns the error: The provided XML has too many elements: 4,004. The maximum is 2,048.; majorErrorCode=400; minorErrorCode=BAD_REQUEST; vendorSpecificErrorCode=null;
This method does not work for me either.