After doing some additional research I think I found the response to my first question at :
Exposing the service to ServiceMix internal bus
We can go a step beyond and try to expose the same service to ServiceMix internal bus (NMR) so that we can connect it to multiple components (BPEL engine, Rules engine, XSLT engine, etc...). We will see that in the next example.
So if I understood well the response is yes. A ODE Bpel process can access CXF web service provider which endpoint is exposed to the NMR.
For the second question I think the response is yes, http bc provider components are required so a bpel process can access external web services providers, based on this page :
ODE now relies strictly on abstract web service definitions (i.e., without binding/service/port definitions), meaning that you only need abstract WSDLs when compiling processes. Since JBI uses normalized messages (in theory, at least), there is no need to define bindings for the BPEL service engine.
In deploy.xml, you simply define the JBI internal endpoints invoked or provided by your partnerLinks,
One may use JBI binding components to make services externally available and therefore providing concrete bindings to those binding components.
Please reply to this post if you think this is not correct.
Edited by: marcelcasado on Jun 1, 2009 5:35 PM