All the interceptors which are configured to the CXF enpdoint will be used if you are using CXF_MESSAGE dataformat.
The message body will be truned into a Dom to let the interceptors handle the message, and you can get the whole soap envolp from camel message body.
The message body can be got as Dom means the soap envelope can be manipulated a XML right? like we can use xslt to tranform the soap envelope (like we can do when dataFormat is MESSAGE)?
Yes, you can use the xslt to transform the message.