XML Schema question

I've been looking again at this MicroXSD subset of W3C XML Schema
and thought I had made a glaring omission but now I wonder whether
the omission is actually there in proper W3C XML Schema. As I try
to write examples of how to use the subset I have started with simple
'Hello World' XML

<Hello>World</Hello>

Now to write a schema for this is easy - just use a simpleType - simple!
I tell the reader they can use <restriction base="string"/> to say that
the content of the element is to be a string. Fine.

But next I just want to add an attribute, say

<Hello from="Steve">World</Hello>

Why should that be difficult? I just want to keep on saying that the content
of the element is a string though. To add an attribute I understand I have
to switch to a complexType, don't I? But how on earth do I do that AND
keep my strong typng of the element content? Am I missing the obvious?

When faced with this before I dropped the datatyping of the element and
specified mixed content for the complexType but surely that's not necessary
is it?

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Stephen D Green