Xtext doesn't generate a project wizard by default. If you want this wizard, you have to add a fragment to your DSL generation workflow and relaunch the workflow.
fragment = projectWizard.SimpleProjectWizardFragment {
generatorProjectName = "${projectName}.generator"
modelFileExtension = file.extensions
}
Then, you have to merge plugin.xml with plugin_gen.xml from ui plugin. A new extension point has been added:
<extension point="org.eclipse.ui.newWizards">
<wizard category="org.eclipse.xtext.projectwiz"
class="org.eclipse.xtext.example.domainmodel.ui.DomainmodelExecutableExtensionFactory:org.eclipse.xtext.example.domainmodel.ui.wizard.DomainmodelNewProjectWizard"
id="org.eclipse.xtext.example.domainmodel.ui.wizard.DomainmodelNewProjectWizard"
name="Domainmodel Project"
project="true">
</wizard>
</extension>
More informations here.