Nowadays, more and more users using the web services like Facebook, Twitter, and Gmail. For a BPEL engine targeting end-user, it will be quite useful to support those "advanced RESTful services" that require OAuth, API key, and multipart HTTP request/response as well as reuse the BPEL process that the user created previously. In this work, we present the service composition engine, a lightweight BPEL engine that supports "advanced RESTful services" and BPEL subprocess on the mobile device. We extend the WSDL for "advanced RESTful services" and BPEL subprocess to be able to compose on the service composition engine.