SDO problem: No escaping of special characters during (un)marshalling

I'm using SDO's over RMI in Tuscany 1.6.1.
I'm running into a problem when the SDO has a String attribute
(defined as <xsd:string>) and the string contains valid UTF-8
characters that are illegal in XML (e.g. '\u001f'). The SDO gets
serialized without escaping/encoding these bytes.

When I later try to unmarshal these objects, the unmarshaller
crashes.

Is that a documented restriction on SDOs? I found nothing in the
spec. It seems to say quite simply that <xsd:string> is mapped to java.lang.String,
so I am inclined to view this as a bug.

I attach a little Eclipse project that demonstrates the problem.
Unzip, compile, run server.Launcher, then run client.Client.
You'll get the exception in Client.java line 44.

After the service invocation, Tuscany SCA correctly returns an object of type DynamicDataObjectImpl to the RMI
marshalling framework. The problem occurs when RMI marshals and unmarshals the DynamicDataObjectImpl object.
This is presumably because the writeExternal() and readExternal() methods of DynamicDataObjectImpl don't support
special characters embedded in strings.