Re:

Sergey,

> But what if each part contains multiple endpoints itself ? <p:Part>, for
> example, might not only contain a specification URI, but also have a 
list
> of vendor' URIs, etc.

If the message contains multiple endpoints of different interface types, 
then you use a <endpoint> for each. The <endpoint> element is a child of 
<input>, <output> or <fault> and can appear many times within each.
e.g.
<input>
        <endpoint name="partUri" interface="tns:PartInterface" ..../>
        <endpoint name="specUri" interface="tns:SpecInterface" .../>
</input>

Arthur Ryman,