SOAP With Attachment MTOM

Hi All

I understand that soap with attachment can be achieved only in SOAP 1.2.

I downloaded the WmSOAPSamples package provided by advantage and i noticed that the example service seems to take String with content type as base64Binary as input and provides the same as output.

I want to know if all attachment can be sent and received only in this format(String with content type as base64Binary).

I am aware that the “Attachment enabled” tab can be set to true only when the webservice provider is created by setting the SOAP Version as 1.2.

But for the sample service provided in the WmSOAPSamples package i created a webservice provider with SOAP Version set to 1.1 and i was able to successfully consume the service.

If all attachments will be in the form of String(String with content type as base64Binary) i want to understand why this cannot be achieved using SOAP 1.1.

I am very new to SOAP with attachment and i dont find a lot of information in the forums as well,so any information in regards to this will be really helpful.

Thanks in Advance