how to Call Webservice inside PL/SQL with serializable Class in Prameter?

Question

how can i call a web-service inside a Pl/SQL with a serialize class in the parameters.

knowing that i need to get data from pl/sql and pass it to another web-service which will return the result as XML.

so shall i take the data from PL/SQL as data-table or can the PL/SQL understand such complex Type as the class.

if either of them how then shall i call it.