Last weekend, I had a tough time trying to call some webservices from my oracle 11g database. I tried loading all the required jars from my jdev 10.1.3.3 into the database, but still things did not work. Finally I found this wonderful post which helped me fix the things in no time. It has an excellent step by step approach for configuring the oracle11g database to call webservices.
PS : If your database is that of an apps instance and if your loadjava , update the JAVA_HOME variable in it point the correct path
Keep watching the blog to know how to call a webservice using Java Stored Procedure.