I am currently developing xsd in Visual Studio .net but I think the question may possibly be relevant still.
If I create a complex type (say myType1) with a key field. Then create subtypes (myType11, myType12 for example) which inherit myType1 using the extension semantic. Next I instantiate these types in my schema. Finally I want to reference the key of say myInstance11:myType11 from another part of the schema which I do with the keyref keyword.
In the schema view there is no complete link from the keyref element to the key element. This leads me to a couple of questions:
1. have I misunderstood the inheritance of xsd?
2. is there a promlem with the Visual Studio schema view tool
3. Am I misunderstanding the use of keys and keyrefs?