Schematron with relative paths for document functions

I have schematron that has configuration files it reads into variables such as

<sch:let name="countriesList"
            value="document('../../CVE/Countries.xml')//cve:CVE/cve:Enumeration/cve:Term/cve:Value"/>

The ../.. path is relative to where the .sch file is. This works fine for executing the schematron from oxygen but when I put 

<p:validate-with-schematron>
            <p:documentation>
                Schematron validate the source doc against the schematron.
            </p:documentation>
            <p:input port="schema">
                <p:document href="../Schematron/test.sch"/>
            </p:input>
            <p:with-param name="allow-foreign" select="'true'"/>
        </p:validate-with-schematron>

I get errors that Countries.xml does not exist at a path that would coincide with starting at the location of the input document not the .sch file. 

What obvious thing am I missing?

Bob Stuart