18. The method as claimed in claim 17 , further comprising: recognizing that the XCAP PUT request message is a request message for creating the XML document when the XDMS receives the XCAP PUT request message; checking whether the XDMC is authorized to create the XML document in a directory; checking whether the XML document is stored according to the first XCAP URI when the XDMC is authorized to create the XML document in the directory; checking whether the XDMC is authorized to retrieve a corresponding XML document when the XML document is stored according to the first XCAP URI; and retrieving the XML document according to the first XCAP URI and storing the retrieved XML document in the second storage position when the XML document is stored according to the first XCAP URI and when the XDMC is authorized to retrieve the corresponding XML document.
19. The method as claimed in claim 18 , further comprising: transmitting an XCAP GET request message to a different XDMS storing the XML document according to the first XCAP URI, when the XML document is not stored in the XDMS according to the first XCAP URI, and receiving the XML document according to the XCAP URI; checking if the XDMC is authorized to retrieve a corresponding XML document by using a user ID contained in the XCAP PUT request when the XML document is stored in the XDMS according to the first XCAP URI; and retrieving the XML document according to the first XCAP URI when the XDMC is authorized to retrieve the corresponding XML document.