You don't need anything in your WSDL and you don't need to enable inline file. it can be false.
You can send the attachments as unknown type. i.e, directly add the attachment in soap UI under attachments tab.
After sending the message form SOAPUI, monitor your sender channel and open the message. You should see two entries (one for the actual xml and the other containing the attachment) under message content -> message part.
>>>> in the adapter engen I find it with ' waiting' statuts
Open that message and go to Audit log and share the screen shot with us