XML Schema creation theory

Question

i've a web app which should create a xml file but I am a while out of school and need some help. This is my form which I want to put in a XML file. As you see I only need the Username/Password for Authentication just in case the checkbox is checked. And I need one defined variable for the authentication method. The authentication radio selection could be the attribute? How would you do this?

I would start with:

<xsd:complexeType name="connection">
    <xsd:sequence>
        <xsd:element name="uri" text="xs:string"/ minOccurs="1" maxOccurs="1">
    </xsd:sequence>
</xsd:complexeType> 

But how can I model the checkboxs? How can I restrict the file to: If a proxy password is set, there must be a username. Thanks

Answer 1

Check-out XForms. Looks like you're trying to solve the same sort of problems.