It shows how to create an input map for multiple documents.
But it sounds like you're asking how to create a WSDL that allows you to use an input map as an argument in a Web Service invocation. If so, take a look at the Assembler services WSDL. For 8.2, access
I don't know how to attach a map of documents but this knowledge base article explains how to attach documents to the SOAP call using the Web Service service in a process:
I hope this is helpful
The document Scott pointed out should be helpful.
I know this site well, but I haven't found how I can create a SOAP request with a docmap if I don't know in advance, how many documents I will need to send. In an attachment I can send only one document, to send documents as base64 encoded text is nonsense and a File URL hasn't worked.
It works well when I know quantity.