It works for basic types, but not for any type where a new C++ type is needed. Here's a branch where I started looking into it, with a new method added to the example extension which hits the breakage: <http://git.collabora.co.uk/?p=user/wjt/telepathy-qt4.git;a=shortlog;h=refs/heads/external-type> I got lost in a tangled mess of trying to figure out which variables are meant to hold Type_Name, which are meant to hold TypeName, and which are meant to hold Namespace::TypeName, and gave up.
Here's my branch with Will's 2 original patches (to improve error reporting and to test external types) and my 2 patches to fix the bug.
The patch seems to do its job admirably. Merged to master. Will be in 0.3.13 (although it doesn't affect the library proper in any way, just anybody using our tools!).
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.