Smooks Bean is null in Freemarker Expression

Issue

We are developing a Smooks project with freemarker expressions and apparently the bean is undefined at the expression level, although it was added previously to the beans on Smooks BeanContext.

As far as we know we should access an added Bean( “x” ) through :

        <ftl:template><!--<#ftl ns_prefixes={"S":"urn:sample:com:xsd:pain.001"}>
${x}
--></ftl:template>

But an exception is thrown reporting that x is not a known expression:

ERROR [freemarker.runtime] (Camel (camel-8) thread #8 - file:///input) Template processing error: "Expression x is undefined on line 2, column 3 in free-marker-template.": freemarker.core.InvalidReferenceException: Expression x is undefined on line 2, column 3 in free-marker-template.
    at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:125)
    at freemarker.core.Expression.getStringValue(Expression.java:118)
    at freemarker.core.Expression.getStringValue(Expression.java:93)
    at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
    at freemarker.core.Environment.visit(Environment.java:221)
    at freemarker.core.MixedContent.accept(MixedContent.java:92)
    at freemarker.core.Environment.visit(Environment.java:221)
    at freemarker.core.Environment.process(Environment.java:199)
    at freemarker.template.Template.process(Template.java:259)