The development of this functionality has been done, but it is not yet available in a published build, the planned ETA is May 2014.
Texo supports xcore in the same way as an ecore model file. All the code generation functionality is also supported for xcore files. You can even specify an annotations model on the basis of the xcore file, load the referenced xcore file as any standard resource in the annotationsmodel file.
To try the different functionalities right click on the xcore file:
The available options are the same as for an ecore file. There is an additional option to generate an ecore file, for your convenience.
Auto-generate EMF and Texo code
You can tell Texo to automatically generate the model code when model files change. Also Xcore can auto-generate the EMF code.
The Texo autocode generation will generate in the same plugin/project as where the model files are located. The EMF code can be generated in a separate plugin/project. Combining Texo code and EMF code fits perfect in a three tier architecture supported by Texo: EMF on the RCP client and Texo on the server.
If you are only coding for the server side you can disable the EMF XCore auto generate feature. To disable the EMF Xcore auto generation uncheck the 'Compiler is actived' option in the project properties: