[libvirt-users] how to change existing domain xml?

Hi. I'm trying to change network settings for a domain via libvirt (the driver is xenapi) with no success. According to its sources, 'virsh edit' uses virDomainGetXMLDesc(), allows to edit the received xml and then use virDomainDefineXML(). In case of xenapi driver it leads to a new vm creation (with the same name and edited settings). Looking through the list of API functions I failed to find a function like virDomainUpdateXML() that would change configuration of existing domain. Could you please suggest a way to do it? Thanks in advance.