NUM Formatting in XSD

While creating a XML layout, I need to format one colom as a NUM. the output will now drop the leading 0 from the output when available, so 001 wil become 1 and that should not be happening. The field should have 6 charaters, when the output start with a 0 this will be droped. Is their a way to ensure that IF the output is less then 6, a leading 0 wil be added.

This is what i have now

 <xsd:element name="ACCOUNT">
            <xsd:simpleType>
                <xsd:restriction base="ACCOUNTtype">
                    <xsd:minLength value="6" />
                </xsd:restriction>
            </xsd:simpleType>
        </xsd:element>

Thanks