The Software Defined Networks paradigm aided by the Network Virtualization is a key driver to cope the Internet ossification. There are different proposals to deploy this paradigm, but there is not an integrated or standardized way for the management of networks built with such proposals. In this sense, the network management becomes too complex because multiple solutions must be used by Network Administrators to perform their tasks. In this paper, we introduce a mashup-based approach that allows Network Administrators to customize and combine management solutions, in order to they build composite applications (called SDN Mashups) aiming the integrated management of Virtual Software Defined Networks in heterogeneous environments. We evaluate our approach by building a SDN Mashup for the management of a network slice that uses three distinct Network Operating Systems and by running performance tests, corroborating that the mashup built has small response time.