how to refer to non-namespaced schemas

Hi all,

If I have a schema--call it schema A--with no namespace, and it is imported
by another schema--call it schema B--which does have a namespace (I do this
by using schemaLocation attribute, not namespace attribute), then how does
schema B refer to types in schema A. The reason I ask is because it appears
to be impossible, as there is no namespace so one would have to refer to it
of a QName where there is no prefix. In these cases though, if no namespace
is referenced, then when in schema B non-prefixed type references are
assumed to refer to types in current schema (B).

Thanks,

Kelly Schwarzhoff