Call Submit with User Arguments and Parameters

example.xml

<xforms:submission id="orbeonCustomer-submission" 
        class="fr-service" 
        ref="instance('fr-service-request-instance')" 
        action="http://......./orbeonFormsManager/outstanding.action?userId={xxforms:instance('user-instance')/userId}&amp;accountNumber={xxforms:instance('user-instance')/accountNumber}" 
        method="get" 
        separator="&amp;" 
        serialization="application/xml" 
        mediatype="application/xml" 
        replace="instance" 
        xforms:url-type="resource" 
        instance="fr-service-response-instance" />

Correction
<!-- Load submission -->
    <xforms:submission id="load-submission" serialization="none"
            action="/exist/rest/db/orbeon/forms/{{xxforms:instance('parameters-instance')/form-id}}/{{xxforms:instance('parameters-instance')/document-id}}" validate="false"
            method="get" replace="instance" xxforms:instance="document-instance" f:url-type="resource"/>