Add a parameter called InvocationStatus in the Copy method. This parameter receives an object of type ExternalServiceInvocationStatus, which we previously defined.

      Define_Map For(*INPUT) Class(#ExternalServiceInvocationStatus) Name(#InvocationStatus) Pass(*BY_REFERENCE) Mandatory(*NULL)

And add the following code to read the status from the response object after #Request.DoPost:

     * Get the request status
     If (#InvocationStatus *IsNot *Null)
        #InvocationStatus.FromHttpResponse( #Request.Response )
     Endif

The complete source code of the Copy method after the adjustments (new lines are highlighted in yellow):

     Mthroutine Name(Copy)
        * Parameters
        Define_Map For(*INPUT) Class(#PRIM_DC.UnicodeString) Name(#SourcePath)
        Define_Map For(*INPUT) Class(#PRIM_DC.UnicodeString) Name(#TargetPath)
        Define_Map For(*INPUT) Class(#ExternalServiceInvocationStatus) Name(#InvocationStatus) Pass(*BY_REFERENCE) Mandatory(*NULL)
        * Variables
        Define_Com Class(#XPRIM_UriBuilder) Name(#Url)
        Define_Com Class(#XPRIM_HttpRequest) Name(#Request)
        * Setup the URL's base properties
        #COM_SELF.SetupUrlBuilder Urlbuilder(#Url)
        * Add the 'copy' path component
        #Url.AddPathComponent Pathcomponent('copy')
        * Add the form parameters
        #Request.Content.AddUrlEncodedFormValue Name('sourcePath') Value(#SourcePath)
        #Request.Content.AddUrlEncodedFormValue Name('targetPath') Value(#TargetPath)
        * Execute the HTTP request
        #Request.DoPost Url(#Url)
        * Get the request status
        If (#InvocationStatus *IsNot *Null)
           #InvocationStatus.FromHttpResponse( #Request.Response )
        Endif
     Endroutine

Next: Testing the Copy Service