XSD schema problem

[Mahmoud]

Hi all,
I have a problem with xml that output from application I need to
validate one of the values by using XSD schema
The xml output like this

<?xml version="1.0" encoding="UTF-8"?>
<csv:csv xmlns:csv="http://xmlns.myapplication.com/2007/message-
format/
csv"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.myapplication.com/2007/
message-format/csv right.xsd" >
<csv:line>
<csv:field>I</csv:field>
<csv:field>3871</csv:field>
<csv:field>0</csv:field> "i want to check this value"
<csv:field>25042008</csv:field>
<csv:field>0</csv:field>
<csv:field>4233</csv:field>
</csv:line>
<csv:line>
<csv:field>I</csv:field>
<csv:field>3871</csv:field>
<csv:field>29042008</csv:field>
<csv:field>25042008</csv:field>
<csv:field>6600183376</csv:field>
<csv:field>4233</csv:field>
<csv:field/>
</csv:line>
<csv:line>
<csv:field>I</csv:field>
<csv:field>3871</csv:field>
<csv:field>29042008</csv:field>
<csv:field>25042008</csv:field>
</csv:line>
</csv:csv>

I get the XSD schema like this

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:csv="http://xmlns.myapplication.com/2007/message-
format/csv" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
attributeFormDefault="unqualified"
elementFormDefault="qualified" targetNamespace="http://
xmlns.myapplication.com/2007/message-format/csv"
xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="csv">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" name="line">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" name="field"
type="xs:string" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>


But the problem that I want to check the value of the third tag
<csv:field> to know if it contain 0 or 1
Can anyone help me to write this XSD