Defining Xlink in XMLschema

Hi

Can anyone help me with these questions?

If I wanted to include inline xlinks within a document e.g.

<rhyme>The <link xmlns:xlink="http://www.w3c.org/1999/xlink"
xlink:href="cat.png" xlink:show="new" xlink:title="cat">cat</link> sat on
the mat</rhyme>

1.    Presumably <rhyme> and any other elements containing <link> need to be
mixed elements declaring <link> as a child in the schema - but is there a
way of declaring <link> just once in the schema so that it can be used
within any elements at random?

2.    (Main question) Do I still have to declare the xlink attributes in the
schema, i.e. href, show and title, or is this unnecessary because I have
declared the Xlink namespace within <link> already?

Thanks

Charles