Write unsigned char property on XML

I use plain orocos and use an unsigned char __u8 as a property of a component. I want to write the property on an XML file so I added the systems type as follows

      #include <rtt/typekit/StdTypeInfo.hpp>
             RTT::types::Types()->addType( new RTT::types::StdTypeInfo0("uchar"));
But still I cant get to write the xml file. Rather I get the following warning log.

         3.530 [ Warning][PropertyLoader::store] Don't know type uchar of x_val and could not convert or decompose it. Dropping it.
Any help is appreciated.