1-Importing Web Service: It uses DomainToXMLmapping when It calls published WS Which has a parameter input,in case that input parameter is a list, the DomainToXMLmapping should map a list that I am trying to obtain it through calling a micro-flow that return that list the problem that after running it raise the following exception to me "Mapping object type '' does not correspond with argument [null]" and I don't know why the break point that i put in this micro-flow does not invoked . 2- WSDL file generation: how can i generate WSDL file from published WS to send it to the caller to use it rather than import it through the url. 3-Managing System errors : how can I manage any system error like null pointer exception to return my meaningful custom error if it is thrown. 4-Managing Required/optional parameter error message: to show also custom message rather than "invalid value for parameter ..."