Meta-data and lupdate

I'm playing around with the commenting (etc) mechanics available in Qt's translation engine.
In particular I've noticed that when I run lupdate, it will only pickup changes to meta-data if that translation text does not yet exist in the ts file.

This means that once you have run lupdate once, you cannot modify (add/remove/edit) any meta-data to existing translation text unless you delete your .ts file and start again (obviously problematic on so many levels).

Is there anything I'm missing with regards to meta-data (perhaps I'm not using it the way its intended?) or anything else?

Regards,
Tom

*edit*
An example portion of tr code:

Code:

---

//= E0002
               //~ description Unable to connect to host
               //~ resolution Ensure the host is available and the network connection is available
               /*: %1 Host Address
                 %2 Host Port
                 %3 Error Message */
               tr("E0002: Unable to connect to host at %1:%2\r\n%3").arg(Settings::hostAddress()).arg(Settings::hostPort()).arg(socket->errorString()));

---