This is the final optional parameter to a SoapMethodAttribute that sits on top of methods you might declare in a class derived [say] from SoapService :-

<SoapMethod(action as String,[SoapAction As String],[UniqueMethodName As String])> _
Public Function myMethod(ByVal reqEnv As SoapEnvelope) As SoapEnvelope
....

But, I can't find any description of what this can be used for in the documentation. It sounds potentially promising for something I am looking into.

Can anyone explain its use please ?

This is for overloaded web service functions to specify a unique method name
in the WSDL (and therefore proxy).

You should find documentation in readme/release notes.

[quoted text, click to view]
top of methods you might declare in a class derived [say] from SoapService
:-
[quoted text, click to view]
documentation. It sounds potentially promising for something I am looking
into.
[quoted text, click to view]