[Zope] Change owner from external app

Hi. I am writing an external application and I need to modify owner and permissions of zope files from that app. I thought about using HTTP object publishing or XML-RPC, so I checked documentation at http://www.plope.com/Books/2_7Edition/AppendixB.stx#2-45 but I can't find any method to deal with owner/permissions. Is there really no way to do this or am I just missing something? Thanks in advance. Marek Ludha