How to use groups with mixed content models

[Ben Ryan <b_ryan@c-elect.co.uk>]

Hi,
	I am trying to use the following declarations to give me a content
model that would be expressed as <!ELEMENT title
(#PCDATA|emph|note|target|xref)*> in an XML DTD but I would like to use
element groups to get the same benefits as parameter entities.

Here are the definitions:

<xsd:element name="title">
 <xsd:annotation>
  <xsd:documentation>a descriptive title</xsd:documentation>
 </xsd:annotation>
 <xsd:complexType mixed="true">
  <xsd:group ref="text-model"/>
   </xsd:complexType>
</xsd:element>

<xsd:group name="text-model">
 <xsd:annotation>
  <xsd:documentation>the group of elements that are used inside a text
or paragraph element</xsd:documentation>
 </xsd:annotation>
 <xsd:choice minOccurs="0" maxOccurs="unbounded">
  <xsd:element ref="emph"/>
  <xsd:element ref="note"/>
  <xsd:element ref="target"/>
  <xsd:element ref="xref"/>
  <xsd:any namespace="##other"/>
 </xsd:choice>
</xsd:group>

The following fragments illustrate the problem:

OK

<title>A test title for checking a schema definition</title>
<title><emph>A test title for checking</emph><note>a schema
definition</note></title>
<title>A test title for <emph>checking</emph><note>a
schema</note>definition</title>

BAD
<title><emph>A test title for checking</emph><note>a
schema</note>definition</title>
<title>A test title for <emph>checking</emph> a
<note>schema</note>definition</title>

I assume that it is that the group is not mixed in the sense that a
complex type is or am I completely in the wrong direction?

Any help would be appreciated.

Regards,
	Ben
-- 
***************************
Dr Benjamin Ryan
Senior Technical Consultant
C-Elect
Tel: +(44) 1484 517077
Fax: +(44) 1484 517068
***************************