DR 09-0294 ? OPC: Embedded packages and pack IRI references

[MURATA Makoto (FAMILY Given)]

> Could we resolve this DR by adding a comment that pack IRIs cannot point into embedded packages? 
>It would clear up the standard as it stands and, if we decided to invest
>efforts in this area later, we could always modify the text to add the
>feature.

This approach looks fine to me.   Let's add some normative prose for
explicitly disallowing references to OPC parts in embedded packages.

Cheers,
Makoto