There are also some custom roms out now with pre release builds of tango that may also grant this feature,if you cannot wait for the update you can check this thread for instructions on how to flash a custom rom as well as the unlocker:
http://forum.ppcgeeks.com/htc-arrive...rive-here.html
and then this link here.
http://forum.ppcgeeks.com/htc-arrive...ve-gold_c.html