Schema newbie - stuck for over a week now

I have written an XML doc that's fed into XSLT then XSLFO, it all works fine and pr开发者_C百科oduces lovely formatted pdf's. The schema I have written is throwing an error which is a problem as the structure is the nub of the project.

XML doc example:

<sect>
    <summ>
        <p>
        Here's some text.
        </p>
        <img src="www.someaddress.com"/>
        <p>
        Here's more text.
        </p>
    </summ>
<sect>

The corresponding schema's (to save space I have removed some elements from each of the xs:choice's):

<xs:element name="img">
    <xs:complexType>
        <xs:attribute name="src" type="xs:string" use="required"/>
    </xs:complexType>
</xs:element>

<xs:element name="summ">
    <xs:complexType>
        <xs:choice>
            <xs:element maxOccurs="unbounded" ref="p"/>
            <xs:choice minOccurs="0" maxOccurs="unbounded">
                <xs:element ref="img"/>
            </xs:choice>
         </xs:choice>
         <xs:attribute name="title"/>
    </xs:complexType>
</xs:element>

<xs:element name="sect">
    <xs:complexType mixed="true">           
        <xs:choice maxOccurs="unbounded">
            <xs:element ref="summ"/>
        </xs:choice>
    </xs:complexType>
</xs:element>

<xs:element name="p">
    <xs:complexType mixed="true">
        <xs:choice minOccurs="0" maxOccurs="unbounded">
            <xs:element ref="img"/>
        </xs:choice>
    </xs:complexType>
</xs:element>

I want to be able to allow to appear inside both inside and outside of "p", at the moment when I validate this against the schema it throws an error "cvc-complex-type.2.4.a: Invalid content was found starting with element 'img'. One of '{p}' is expected."

So ideally I'd want the following to be valid:

<sect>
    <summ>
        <p>
        Here's some text.
        </p>
        <img src="www.someaddress.com"/>
        <p>
        <img src="www.someotheraddress.com"/>
        </p>
    </summ>
<sect>

If you can help then I'd be very grateful :)

---

<xs:element name="summ">
<xs:complexType>
    <xs:choice minOccurs="1" maxOccurs="unbounded">
        <xs:element minOccurs="1" ref="p"/>
        <xs:element ref="img"/>
    </xs:choice>
    <xs:attribute name="title"/>
</xs:complexType>