property = element.getModelElementType().getProperty(this.property);
return property != null;

ERROR : Invalid model path "List" evaluated on my.package.IConstant.

<if>
    <condition>
        <class>PropertyExistsCondition</class>
        <parameter>List</parameter>
    </condition>
    <then>
        <include>@composite.value.list</include>
    </then>
    <else>...</else>
</if>

    public ModelProperty getProperty( final String propertyName )
    {
        for( ModelProperty property : getProperties() )
        {
            if( property.getName().equalsIgnoreCase( propertyName ) )
            {
                return property;
            }
        }
        
        return null;
    }

super.initCondition(part, parameter);