webservice as datasource in sql reporting services

hello,
i have a question about using web service as datasource in reporting services
i have a web service which returns dataset
now what should i do, how do i attach this one to report
i saw couple of examples(on data extension ) but i really dint understand how to attach web service to this.i think iam missing some pieces can some one please plese give me step by step instruction like where to start, how to implement this kind of thing and another question my web service needs parameter how i do i implements this

i really appreciate some help

thanks