If you are looking for a solution where you want to invoke a web service from OSB which is using client SSL certificate negotiation then below page can help you on step by step setup you need to do for that.
Page describes what are the resources we need to create(Credential Mapper and Service Key Provider) and how we can configure our proxy and business service to use them for outbound two way ssl certificate negotiation.
Page Link : Client Certificate Authentication for OSB Outbound
Like it if you have learned something. Comment your views, queries. Any suggestion and corrections are always appreciated. Keep learning.
Oracle SOA Tutorials and Solutions 