<?xml version="1.0"?>
<xsd:schema
    targetNamespace="http://www.something.com/2006/stuff"
    elementFormDefault="qualified"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <xsd:complexType name="typeExecutable" mixed="true">
        <xsd:attribute name="type" default="application/xml">
            <xsd:simpleType>
                <xsd:union memberTypes="xsd:integer	xsd:float" />
            </xsd:simpleType>
        </xsd:attribute>
    </xsd:complexType>

</xsd:schema>