How to test DIME Attachment using ReadyAPI ?

Old web services using DIME binary attachment standard.  I have a link to old MSDN documentation:

DIME: Sending Binary Data with Your SOAP Messages

 

Last time I checked SoapUI documentation, I could not find support for testing with this attachment type.

Now that we are using ReadyAPI, does anyone know if/how we can test using DIME binary attachment type?

 

Thanks,

Eric