I'm new to serviceMix and CXF. I just set up cxf-osgi sample and it was running well. However, this sample web service only accepts a request with a string parameter and sends a response back. If I need to send a soap attachment to this webservice, I'm not sure how I can change that sample in order to retrieve the attachment?
You can take a look at the samples which are shipped with CXF.
There is an example which name is "mtom" shows you how to use the soap attachement with CXF.